These insurance companies that are pulling out of CA and FL have done business in those states for ever, but now they can’t afford to stay because something changed. In California, it’s that we’re having a lot more frequent and severe fires. In FL, IIRC, it’s more frequent and severe storm damage. What would have changed that would cause these things? Gosh, I feel like it’s on the tip of my tongue.

You're not wrong, but it actually gets worse than that. Florida specifically has made an ever increasing hostile environment for home owners insurance companies specifically. The way the Florida laws work make it very easy for rampant fraud to happen. Florida home owners basically know that you should never pay to replace your own roof, that's what insurance is for. Every time there's the lightest hailstorm or tropical storm you'll have storm chasers handing out fliers in neighborhoods promising to get your roof repaired at very low prices. These companies then turn around and essentially sue the insurance companies. This is just one of the ways that it's become unprofitable to run insurance in FL, but there's many and FL legislature is fighting to make it worse every day.