Developers are not rolling in cash, they are struggling to find opportunities to build housing, especially entry-level homes, at a price they can actually sell.  Their are only so many buyers for luxury homes and they're running out.

This video and article from CNBC explains it very well:
https://www.cnbc.com/2016/05/18/for-homebuilders-new-regulations-mean-no-new-starter-homes.html