[Maypeevophy]

My thoughts:
1. Insurers can undercharge certain customers and overcharge other customers. The ones that overcharge risky customers lose the risky customers, increasing their profitability, and the ones that undercharge risky customers default.
2. Customers don't switch easily or frequently and won't switch on a dime because the price is slightly lower, thus we don't get a price reduction spiral.
3. Insurance companies actually have insurance themselves.
4. Legislation?