It wasnt the down payment that was the problem.
It was giving loans to people who had no income.
If we let the banks, and their underwriters do their jobs we will be fine. it is when the government steps in and says they will underwrite and guarantee mortgages for people who would otherwise not qualify that we get into trouble.
Banks Push Home Buyers to Put Down More Cash
"A 2009 Federal Reserve Bank of St. Louis study concluded buyers who made smaller down payments were more likely to default during “unfavorable economic circumstances, such as a housing market slowdown or job loss.”"