New York is currently having the biggest boom in sky scraper building since the 1930s. My brother is a construction manager on a 70 story building that's going up right now, and it's not even in the top 25 building projects currently happening in NYC.
Only 3 of the top 22 buildings in NYC existed 10 years ago, and I'm considering the WTC to be one building. If you count rebuilding the WTC as a new building, then the only two older sky scrappers in the top 22 are the Empire State Building and Chrysler Building. Everything else is less than 10 years old or currently under construction.
http://ny.curbed.com/maps/mapping-the-rise-of-new-york-citys...
[1] http://www.amny.com/real-estate/nyc-skyscrapers-tallest-buil... [2] http://www.nytimes.com/2016/02/18/nyregion/developers-plan-s...
Maybe you just mean San Francisco?
This random list is a bit dated (2013) but many of these buildings are nearing completion and many more have started planning or construction:
http://sf.curbed.com/maps/26-high-rise-projects-changing-san...
I think why you don't hear about many cities in America building super-large skyscrapers is threefold: 1) The U.S. is still a very large country with lots of room, especially away from the coasts 2) Construction costs of super-tall buildings scale nonlinearly, so buildings taller than 55 stories tend to not pay off per the square footage value of renting/selling, so mid-scale buildings are generally more profitable 3) Geographic agglomerations mean that creative class folks (like developers) tend to be attracted to existing large cities like SF, Seattle, and NYC
ADDED: As others have said, there are plenty of skyscrapers going up in cities like New York. What you don't have going on as much in the US these days are the very tall iconic prestige/vanity projects that get all the press.
Perhaps that's what I'm thinking of then. Also, I don't live in Manhattan or SF (the cities I'm familiar with include Atlanta, Charlotte, Nashville, etc.)
2. Density has become less important over the years. Inexpensive worldwide transportation, and instant communication means you don't need some huge office building HQ. Instead you can have a collection of cheaper office parks distributed over several cities.
3. Skyscrapers are still built regularly, but only where demand justifies their construction.
There is still a huge value to proximity. Sure, you can replace talking formally about a work problem in person with teleconference. You know what you can't replace with teleconference? Going out for lunch. Going out for drinks. Running into someone. The "vague" social schmoozing which is officially not important but in practice can be when all kinds of things get done, informally.
We are building lots of skyscrapers, but they are mundane in comparison to the vanity/PR/pride projects that are going up in other countries that are setting records for height, space, etc. So if you're reading the news you're much more likely to read about projects in the UAE or China than here.
IMO this is perfectly fine - I for one like it when buildings can economically justify themselves rather than be subsidized in the name of national/regional pride.