Good point. If 95%-100% financing dries up even for people with good credit, then the pool of first time home buyers will shrink to almost zero. It will be people who can get big down payments made by Dad and Mom, or people with great jobs who have also been renting for several years.
Of course, if comps are based on prices of closed sales from 3-6 months ago, and the current sales price is 5-10% less, then there might be the illusion of less than 100% financing. That might let these no-cash down first timers buy for a little while longer.