I don't think you understand actuarial math. There is a risk reward for every ensured item/person, the idea is you spread out the cost based on statistics and keep a percentage for profit/bookkeeping. Not every home is going to be flooded in a flood, but many homes have to be insured to make the math work. Even if someone/something has a pre-existing condition/propensity to disaster, there is a cost curve to it. In some cases it can actually be cost effective, as those who know it are more likely to manage their risks. Insurance is a greater than zero fund, some things cost more, some things cost less.
There are plenty of pool based economies. For example, many tax dollars are routed to border, flood, earthquake, etc areas from areas that have no reason to do so. It would be cheaper for everyone to live on a bedrock hill where bad weather was rare, but no one is proposing that.
The big difference here is private companies are managing these situations.