Good luck finding such insurance. It simply isn't available and if it was it would not be at a reasonable cost. As a result the airlines 'self-insure'. i.e. they don't give money to an insurance company, but pay out valid claims from their own reserves.
fair enough, but thats their choice. Its one of the risk of taking folks money to deliver something which you may not be able to insure against. I do however disbelieve that an airline cannot get insurance at a reasonable price - its just that they don't want to buy anything that would increase their fixed cost base. And thats entirely their choice.
So if the car hire firm was unable to supply a car because car hire was banned following an environmental disaster then they should be expected to look after you until car hire became permissible again? Well that's a lot less bother than worrying about old-fashioned travel and credit card insurance.
Yes they should. Thats assuming that there were no alternative travel methods of course, so my example was poor.
If a business is going to take someones money for doing something, then they should not expect others to suffer because they cannot deliver against insurable risks. If they don't want to pay the insurance costs, then its not reasonable to expect to take folks money and just say 'tough luck'.