The rich don't really care about insurance rates down here because they can a) pay them, b) tend to gravitate towards newer buildings that have better protection and c) have the money to retrofit older buildings with the necessary protection to lower insurance rates. Miami has the strictest hurricane codes in the country, so while there's a possibility that they may get gutted, it's probably going to be less than people expect.
I live in FL so if you have questions about insurance feel free to ask.
But the people who can easily afford the insurance in Florida can afford the new tax as well. And as an added bonus, they don't have to live in Florida!
But in all seriousness, they all already own homes in Florida.
So they can pay the higher insurance without a thought, they can pay for the relocation across the country, but they're unwilling to finance public services for the city they live in.