As long as you can admit that a greedy buyer has no one to blame except themself, fine. Otherwise, I take your continued comment as trying to excuse them.
I would no more excuse them than an alcoholic, you work for a lender or something because you seem to be apologizing for them.
In my case, specifically, I knew there was going to be trouble when I purchased a house 20-ish years ago. I was pre-approved for a loan where the payments met (actually, slightly exceeded) my monthly net income, and I got that far with little more than a signature and a paystub.
Obviously, I was smart enough not to buy a house that would leave me unable to afford luxuries like water, electricity, and food. But there are plenty of people who aren't that smart, and plenty of predatory lenders or "affordable housing" (read: diversity) advocates who are happy to take advantage for a quick buck.
Contrast this with my next home purchase where I was pre-approved for exactly the amount needed, not a nickel more, and had to jump through a myriad of hoops just to get that far. It was the same bank, and its internal controls were ratcheted down, to be certain.