If they're smart insurers, they would leave before there are actual losses, because there's a pretty significant lag time between when you write the policy and when the customer makes a claim. By the time there's a major disaster, it's too late: they'll be bankrupt if they didn't collect premiums at a rate that makes the disaster survivable.

If you believe that insurance is still profitable at the rates where other insurers leave the market, the rational response is to start your own insurance company. Run the numbers and prepare a presentation to investors; if your numbers are rational and convincing, you can capture the market for yourself and reap the profits.