Wall St. Banks caused the financial crisis. The key element of this crisis was the creation of a housing bubble. Real estate prices escalated way past incomes. These same banks created incentives up and down the mortgage chain to lure/push buyers into predatory loans and to buy at inflated prices.
It’s now clear (from Congressional hearings) that these banks knew the bubble would burst. This has left millions of homeowners with “underwater” loans (real value less than loan value). The banks should restore health to those borrowers, to their communities, and to the financial system by reducing principal and redoing loans at the real current value, which is also the historic trend value had the bubble not occurred.