America is the birthplace of skyscraper, in last century, most skyscrapers in the world were located in America, New York City and Chicago are the best representatives of skyscraper cities, and the crown of World's Tallest Building had been owned by buildings in America, until in 1997 when Petronas Towers in Malaysia overtook that crown from Sears Tower with their decorative spires.
But after that, Asian countries keep building more and more skyscrapers, Dubai, China, and some Southeast Asian countries are best representatives, as in recent years the majority of newly built skyscrapers are located in these places. With the current speed, the total number of skyscrapers above 500 feet in China will be 4 times of the number in America within a few years.
Not only so, many megatall skyscrapers have been successfully built in China, while America's tallest building by roof height is still Sears Tower (One World Trade Center is not really taller than Sears Tower, its roof, highest occupied floor and observation deck are all much lower than Sears Tower, which is a building built in 1970s), megatall is still in vision stage in America.
So why America doesn't build tallest buildings again? Below are some factors that may cause that.
The height of a skyscraper is subject to the restriction of technology, for instance, in 1930s, Empire State Building was the tallest building that the technology of that time could handle. As of now American construction companies have not built a single skyscraper taller than 500 meters yet, it's unknown whether their technology could complete a building that tall, Chicago Spire was reported to have construction difficulties.
In the field of construction, China is leading the world, as of 2019, the country's construction companies have built seven 500 m+ skyscrapers in their own country (with the ones topped out but not fully complete included).
Not only so, with their technology the construction speed becomes much faster, a building that typically requires five years to complete may takes only three years by using their technology, and a supertall can be built to the full height within a year. An example is The Exchange 106 in Kuala Lumpur, the tower was supposed to be complete by 2023, but after the Chinese construction company was contracted to build the tower, the estimated completion date is scheduled in advance to 2018, and they have almost done it, the building is close to top out as of early 2018. By contrast, One World Trade Center, a building of 417 m by roof height, took 8 years to complete.
Unlike other countries like UAE or Malaysia, in which the tallest buildings were built by foreign construction companies, American prefer to contract the local construction companies to build skyscrapers, now some large projects in America are being managed by some Chinese developers, but the contractors for the projects are still local companies, they are unlikely to contract Chinese construction companies or some other companies with enough megatall-constructing experiences like Samsung C&T.
Height Limitation set by FAA
The United States has a rare nationwide height restriction on all kinds of man made structures. The FAA doesn't allow skyscrapers to be built higher than 2000 ft in most cases to make the airlines more secure, and the restriction is even stricter in some cities in which the airports are built in close proximity of the city center, like in Seattle and Miami, skyscrapers generally can't be built to much higher than 1000 ft.
However, we can't blame FAA for tallest buildings are not being built in America, because that height of restriction is still considered quite high, even Ping An Finance Center(One of the best representatives of megatall skyscrapers in China) is only 1965 ft, and Shanghai Tower(second tallest building in the world) is no more than 2000 ft if the height of parapet is not counted. We really can't blame the height restriction until some buildings get built to close 2000 ft in America.
In Singapore, there's also a height restriction for buildings in CBD area, now the area has already have three buildings built exactly as tall as the height of restriction, only in this case the restriction can be condemned.
Lack of Available Land
In American cities like New York City or Los Angeles, most land in city is already being occupied by existing buildings, to find a flat land for a new skyscraper is not easy, available flat land like Hudson Yards is in the minority, in most cases developers must first purchase the old buildings for the land, and then demolish them, higher buildings typically require larger bases, which means for developer to purchase more buildings (Before the construction on Sears Tower began, Sears bought a whole block of buildings to make space for the building). Technically they can still build tallest buildings, but the higher cost can still set back many developers.
NIMBY & Approval
In some cities like San Francisco, shadow cast on nearby residential buildings can always prevent skyscrapers from being approved to be built higher, for instance, the Salesforce Tower was initially planned to be 370 meters but scaled down to only 326 meters due to the shadow issue.
In New York City, the shadow cast on Central Park by the newly built supertall towers on 57th street had sparked some protects. The Municipal Art Society is reported to be looking for a way to curtail New York City's supertall boom.
Donald Trump had ever planned to build a world's tallest skyscraper in New York City in 1985, named Television City Tower, the building was designed to be 1670 feet tall, has 130 stories, it was planned to be built at the riverside on West 66th Street. Trump also had NBC signed as the anchor tenant for his building. However, some local community groups don't like the building and fought Trump's proposal, making the proposal cancelled at last.
In China, things is totally different, it is well known that the authorities can directly ask the nearby residents to move away to make space for a skyscraper, not to say protects for shadow cast.
Many people think that as a developed country, America has no demand for more skyscrapers. This is not true, populations are growing, which means more houses and buildings need to be built to accommodate these new comers, that is why New York City is having so many supertall residential buildings being built.
In China and Middle East, one of the major motives for developing tallest buildings is to improve the image and prestige of a city. For America, many cities in the country are already pretty well known in the world, they do not need a tallest building to improve the popularity.
Chicago used to have some megatall proposals like World Trade Center, 7 South Dearborn, Post Office Twin Towers. Unfortunately the developers behind these projects are not big players.
Some giant technology companies like Facebook and Apple prefer to choose campus as their headquarters, technology giants own supertall skyscrapers only happened in films, such as in Amazing Spiderman, the headquarters of Oscorp is in a skyscraper named Oscorp Tower.
Many large cooperation believe that a very tall skyscraper may hurt their business, since this did happen in the past, one example is Sears, Sears Group was once the largest retail group in the world, after the Sears Tower got built, it was gradually surpassed by other companies like Walmart, at last Sears sold the building in 1990s. Hong Kong's real estate tycoon Li Ka-shing deliberately built the headquarters of his group shorter than the nearby Bank of China Tower.
Financial difficulties is still the biggest enemy of development of skyscrapers, especially in America where the labor is very expensive.
The former world's tallest building Empire State Building was built in an era when labor was very cheap, most workers were immigrants, nowadays the construction workers in the United States are mostly local American.
Burj Khalifa in Dubai cost 1 billion dollars(1.5 billion dollars with its surrounding facilities) to build, in America, even 426-meter-tall 432 Park Ave cost more than this much, it's also much more slender than Burj Khalifa. If Burj Khalifa is built in New York City, it would cost at least 3 billion dollars.
Moreover, mega-tall skyscrapers built in China are mostly funded by developers themselves, most of these developers are state-owned companies, it's not difficult for these companies to provide finance for their projects. But in America, funds for building skyscrapers come from anchor tenants, individual investors, and lenders like some investment banks, lacking of funds will result in cancellation or postponement of projects, one example is Two World Trade Center, the project is still on hold because the developer can't find an anchor tenant.
In some cases the skyscraper is developed to be the workplace or headquarters for developer itself, like Sears Tower was developed by Sears for itself as its headquarters, in such kind of cases financial difficulties is not a problem for the developers, since these developers are mostly large influential corporations and can directly finance the projects. However, as mentioned earlier, these developers have no interest to build a tallest building as their workplace, for instance, Apple prefers to build their headquarters a ring-shaped structure that has only 4 floors at a cost of $5 billion. This is not indicating that skyscraper is not popular now, some notable companies are still building skyscrapers as their workplace, JPMorgan Chase is planning to demolish their current headquarters building in New York City and replace it with a 1400-feet-high supertall, they just don't want to make it the tallest.