Because the people issuing those mortgages will be long retired by the time it comes home to roost and also they are probably banking on a federal govt bailout.
If you mortgage a property and the property is destroyed, you are still on the hook to repay the loan. If you have insurance that will cover it, then great. If not, you still owe the note. Sound like sound logic for the banker types.
Except that you don't buy insurance in 40 year contracts. Once the water gets too close, it will become uninsurable. It would be like selling insurance on a house that is burning.
Nah, some insurance company will continue to take people's money, but when it comes time to make a claim, they will come back with this was not an act of god event, but a malicious man made event. Claim denied!