The US has plenty of unused land. Over 2 billion acres. Only 5-9% of all US land has been developed. Around the US we are seeing a growing trend. Tearing down existing structures, sometimes even large buildings, to replace them with something new and usually much larger. Even in some sleepy suburbs, a large house is torn down to be replaced with a much bigger one or two or more.

The US housing stock is aging. The average US home is about 43 years old. US commercial buildings are about a decade older on average. Often upgrading them to meet the demands of today (not just the amount of space) is more expensive than replacing the whole thing. Often, renovations/rehabs cost more than starting afresh and usually take longer.

Yes, there is tons of land to build more, but it is the prime, most convenient location where things pencil out for a teardown. And in the prime locations it's often easier to charge the kind of pricing needed to be able to cover the (rising) costs of construction. In all of this lies opportunity. Many homes' real value may be the land they are built on.