Development requires demand. You can't just build houses willy nilly and then have them sit empty, because then nobody is paying the property taxes and the infr

Development requires demand. You can't just build houses willy nilly and then have them sit empty, because then nobody is paying the property taxes and the infrastructure that was built for those empty houses requires maintenance. So, while there may be plenty of land on which _to_ develop, they can only develop at a certain rate commensurate with demand, otherwise they'll build too much, property values will fall, and subsequently tax receipts will fall. So, they need to build just enough to keep up with demand, and ahead of their infrastructure costs, but not too much.