Ed Gramlich died recently, but he left us his book on the subprime mortgage market. I have not read it yet but this summary recently came to my attention. It's a refreshing read.
Cycles are natural to the market economy (boom-bust). The boom-side typically involves major innovations and is remarkably productive. The legacy of the full cycle is positive!
The current real estate finance cycle involved significant innovations on the finance side that put people into homes who would not otherwise have them -- most of whom still have them and are likely to keep them.
Gramlich's analysis included some common sense innovations that deserve further discussion.
But common sense sounds downright boring compared to the devil theories that many observers (and politicians) prefer.