Difficulties of Acquiring Air Rights
Furthermore, in some American cities like New York City, having acquired the land space doesn't ensure the developers to build as high as they want on it, since owning the land does not also owning all the air space above it. This is because under the zoning laws, every lot in the city has a maximum density restriction, which varies depending on which zoning district it's located in and some other factors. So by default the building on the lot cannot exceed a limited maximum height, which is affected by the density or floor area of the building, thinner building is less dense, hence allowed to be higher (this is why many pencil-like skyscrapers like 111 West 57th Street started emerging in the city).
Air rights is transferable, if the developer wants to build a building to their desired height that higher than the limit, they can purchase the unused air rights from the adjacent properties. But if they cannot afford it, or the owners of the adjacent properties refuse to sell the air rights (they might don't want their buildings to be dwarfed by a much taller tower, or it would block sun lights, etc.), or there's simply no enough remaining air rights around, they will fail to build a very tall skyscraper.
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 tall 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 protests. 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 and would have 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 against 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 place for a skyscraper, not to say protests for shadow cast.
No demands
Many people think that as a developed country, America has no demand for more skyscrapers. This is not really 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.
No interest
In China and Middle East, one of the major motives for developing tallest buildings is to improve the 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 reputation.
Chicago used to have some megatall proposals like Chicago Spire, World Trade Center, 7 South Dearborn, Post Office Twin Towers. Unfortunately the developers behind these projects are not big players in real estate.
Some giant technology companies such as Facebook and Apple prefer to build a campus as their headquarters, technology giants own supertall skyscrapers only happened in films, like in Amazing Spiderman, the headquarters of Oscorp is in a skyscraper named Oscorp Tower.
In June 2019, it was reported that Facebook is planning to develop a supertall tower in Midtown New York for its workspace in New York City. However not long after the news came out, a person with knowledge of the matter told Bloomberg that Facebook never seriously considered the building.
Many large cooperation in the world 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
Financial difficulties is still the biggest enemy of the development of skyscrapers, especially in America where the labor is very expensive.
The former world's tallest building the 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 432 Park Ave, a building that is only about half as high as the former, cost more than this much.
