[mindslight]

also 3) many "insurance" companies are in the provider game, meaning they can preferentially shuffle surplus to their other arm

(2) and (3) were part of what I meant by a lack of regulatory bandwidth in another comment. There are rules that could be enforced to promptly impose steep penalties for a company that tries to skirt them. But they just aren't, so after one company starts doing it the rest inevitably follow suit.