"If you get to live in a nice home for a few years and then lose it to foreclosure, you are not worse off than someone who never got to live in a nice home in the first place."
So, let's say you put down 20% of the purchase price on a home, and get an adjustable rate mortgage so you can finance the rest of it. You figure that, even though the rate will reset in three years, you'll be able to refi, and get a better rate. However, housing prices have slumped, and now your home is worth only a little more than your mortgage. You can't refi, since you don't meet the LTV requirements that newly conservative lenders are enforcing. You can't afford the new payments, and your home is likely to sit on the market for many months, since there are so many other homes for sale out there.
How is that "not worse off" than someone who rented a place while housing values went in the toilet? The renter has his credit record intact, as well as his equity, which sounds like he's a lot better off than someone who wanted to own his own piece of the American dream.