Besides the fact government interference in the insurance market does more harm than good to those it intends to protect, the wealthy are the ones that most benefit from government flood insurance. The vast majority of people that live in places where insurance is unavailable or too expensive are those wealthy enough to build a house on a hurricane prone beach. (Think too of the fire/earthquake prone hills of glorious sunny California)
What you're really asking for is those of average means to subsidies second beach houses for the rich. Not only is your argument faulty it's immoral.
We're all better off taking care of ourselves than being taken care of by morons. The government solution to a problem is inevitably worse that the problem itself.