Mainly because home insurance companies are playing the same shitty games as health insurance. Instead of someone like Farmers taking policies and spreading the risk across the country, they are creating smaller "boxes" where if a hurricane hits Florida, there aren't enough Florida policies to cover. Nationally, they have the money, but from a business standpoint, they boxed Florida by itself. Then they declare bankruptcy in Florida leaving policy holders with the bag.
I'm on the fence about this. If the actuaries have done the work and determined that massive chunks of the state have a very high risk of expensive hurricane-related claims, shouldn't either the rapidly rising rates, or the refusal to do business in the state altogether, reflect that this isn't a place people should be flocking to in large numbers?
As someone who intentionally chose to make my home a state where we're relatively sheltered from the most destructive extreme weather events, I'm happy that I'm in a separate insurance pool from these extremely risky properties. Keeping things somewhat localized keeps costs cheaper for those making smart decisions, incentivizing others to do the same.
I think it's quite shortsighted that we're incentivizing new development and migration to areas that are going to regularly underwater in a few decades. I understand where you're going with health insurance comparison, but at least with that - there's near universal agreement that we should be investing resources in early detection and interventions to prevent new folks from developing costly pre-existing conditions. I see very little acknowledgement of this when looking at risky land use decisions.
No, just like the people that complain about the fat people in their same insurance pool, you're facing less risk in the larger pool with everyone kicking in premiums. That's what the actuaries say time and time again. Making the pool smaller is far riskier than excluding the "bad" bets. Our workplace insurance did that, separating everyone into the "healthy" and "unhealthy" pools. As I predicted, EVERYONE's rates went up. It is a similar principle on why countries with socialized medicine have far, far cheaper costs than the US.
The Gulf facing states have always had issues with hurricanes. Insurance bailing at the scale we're seeing in Florida is new.