Hugely. It's possible to build extremely tall buildings in certain specific areas of Manhattan (and New York in general, like in Downtown Brooklyn), but most of

Hugely. It's possible to build extremely tall buildings in certain specific areas of Manhattan (and New York in general, like in Downtown Brooklyn), but most of the city is "maxed out" to its zoning - that is, the tallest building that can be legally built is already there. Indeed, in many places, the existing buildings are taller than the zoning code allows - so if you demolished an old building, you'd have to build a shorter one in its place!