The largest banks were bailed out with this same thinking even though there were banks (Wells Fargo, US Bank, etc.) that did not have a lot of bad mortgage paper. If most of the big insurers fail others will step in.
it's not the insurers that matter. It's the hospitals.
Most of them have less than 15 days cash on hand. More than 60% of their money is coming in from PPACA related programs.
Obamacare can't be defunded without nationalization of the system.
Repeal is the only way out, and with Obama in the White House, it is impossible.