And maybe I'm not that convinced.
The problem is very concentrated on adjustable mortgages, and threatening there even to go in the near prime and prime sector. Too low rates as well lead to higher volatility in rates and make therefore adjustables much more dangerous. As an example look to the variation of lead interest set by the Fed and by the ECB over one cycle. The ECB goes about from 2 - 4%, so we are speaking of a doubling. The Fed goes from 1 - 5.25 % or so, that is more than a fivefold.
With negative interest rates, as the US had for some time, it simply makes sense to buy tinned food on credit and sell it later for profit.

Der Amerikaner ist die Orchidee unter den Menschen
Volker Pispers