No, you're not talking strictly about the consumer. You asked what responsibility homeowners have, so you're literally asking to weigh their "responsibility" against other factors involved with why the crash happened. And this is not about the literacy of the consumer. That's one relatively minor aspect that you're choosing to highlight in this thread.
Asking how much "responsibility" the homeowners have in the crash is a peculiar question. They were people who were hoodwinked into getting mortgages they couldn't afford, often though fraud. And it was fraud because mortgage fraud is defined as "the intentional misstatement, misrepresentation, or omission by an applicant or other interest parties, relied on by a lender or underwriter to provide funding for, to purchase, or to insure a mortgage loan." by the FBI. People were given teaser rates that would skyrocket after 6 months and not told, and they were assured that they would be able to refinance, meanwhile the banks were securitizing the mortgages and selling them off right away after getting their cut and they knew exactly what they doing.
So these mortgages buyers had no organizational/planning role in the crisis. They were not aware, nor could they be, that they were somehow inadvertently shaping macroeconomic policy in a deleterious way. They were just trying to buy a house, maybe the most American thing you can possibly do, in accordance with what is ingrained in our national ethos, and the "ownership society" of which our government is actively pursuant to in granting.
Meanwhile, you have people in high levels of government and banking, with a hands-on active role in molding policy and the world economy. The Federal Reserve using the influx of money from oil imports and keeping interest rates unreasonably low, and the federal government with the horribly-run Fannie and Freddie both actively working to fuel the debt-consumption model that created the housing bubble. Angelo Mozilo and the rest of these crooked @ssholes setting the standard of these NINJA-type loans knowing they would get paid regardless if the borrower defaulted. The Fed and the government failing to regulate the derivatives markets and separate commercial and investment banking interests creating a shadow banking system, depending on "financial innovation," all assuming that housing prices could never all drop at once.. The ratings agencies with their greased palms slapping AAA ratings on shyt. Once again, the mortgage bubble would've just been that, a sector crash instead of a global financial system crash if these toxic assets weren't spread as collateral throughout the entire financial system.
They may not have known specifically what would happen and when it would happen, but they knew they were playing with fire, they knew what they were doing was fraudulent, they knew it was unsustainable, and they knew these assets weren't really worth what they were valued as. Read the Goldman Sachs memos uncovered in the fraud investigation. But they kept at it because of greed, pure and simple...and because they knew the politicians they paid off and played golf with would be there to catch them when they fall.
So I blame the people who actually crafted it, at an organizational level. No the people who were tricked by them because they wanted to move their family into a house and were convinced they could.
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This private profits, with socialized risk structure you are trying to temper with regulation needs to thrown in the bushes. IMHO
