The main reason most tract homes have no basements in places like CA and FL is because they aren’t necessary, and it’s cheaper for the builders, because they aren’t required. Per:

“Basements in the United States have largely been a Midwestern or Eastern concept, and for good reason. Where it freezes in the winter, the land contracts and expands and will literally heave the foundation of a house up. Builders in those areas have to take the foundation well below the 4-foot frost line level to anchor it.”

That said, basements have been a huge trend in custom homes in CA for about the last 15 years or so. We’ve done lots of remodels on various properties but not teardowns. Friends who have done teardowns over the past several years have added basements, and it’s extremely popular in the Bay Area to do so.