I have less sympathy for those who "took on too much house," but I wouldn't say "zero."  In many of those cases, the Realtor's and lenders encouraged very high debt-to-income loans, and approved 100% (or more) financing.  I do agree that borrower's have some responsibility to know what they can afford, but the Realtor's and lenders certainly encouraged a lot of that.

Sometimes, the "unaffordable loans" were encouraged with promises that they would be able to refinance after a short period of time. Then the mortgage crisis hit and they were unable to refinance at all.  And, we cannot forget about the "teaser" rates and ARMS that put people into loans they could afford... for a little while - just long enough for the Realtor's to earn a commission and the lender to collect their fees.

More importantly, you are forgetting about the high, long-term unemployment problem we have had.  A lot of those people bought within their means, but couldn't keep up with payments after being unemployed for an extended period of time.  Most of the people I have represented in foreclosure had lost a job and had to take a position paying far less than they made when they took out their mortgages; and, one was the result of a deceased spouse.  So, it isn't always the borrower's fault.