If you want "solidarity" you need a government service. Private insurance has every incentive to price things accurately and not subsidize higher-risk people. If you tell insurance companies what they have to charge, they have every reason to say "nope, I don't want to offer that service at that price, that doesn't make economic sense".

Incentivizing people to build homes that are likely enough to burn down as to be economically uninsurable is an absolutely wild abuse of the term "solidarity". Solidarity is the idea that an injury to one is an injury to all, not the idea that choices should have no consequences and the environment shouldn't constrain humans; the only way you can possibly sustain a world in which people actually treat an injury to one as an injury to all, is together with some effort to avoid people from gratuitously exposing themselves to injury.