Yes, the leverage the banks asked for was a bad idea. Coincidentally, 4/5 of those banks either don't exist or don't do i-banking.

But quants along with other strats (macro, long/short, etc) all had bad risk management models. You can't blame only program trading when there was so much human error.

Also: quants (meaning algorithmic trading) did not show how MBS were good. That was human error; Moody's and S&P ratings, for example.