This goes back to regulations.
When HMOs first came on the scene, everyone thought, "WOW! $5. to see a doctor."
Many of the PPO & individual payers said "WHOA!!!! Somethings wrong. This can't last".
It didn't.
What it did do was create a whole generation (plus their subsequent children, etc) who thought that health-tunes up (just like your car), would save them money. Who believe that if you have the sniffles, you 'd better got see a doctor (after all, it's only $20) to make sure you don't have some serious island hopping sub-tropical malady from the tse-tse fly.
Then, these twits started calling their local politicians, who also thought that healthcare is a right (as long as it got them re-elected) & told insurance companies they had damn well better cover colonoscopies & mammograms & child well-care & blah blah blah. In fact, several years ago, most insurers did not cover birth control at all. Until government forced them to put it on their plans.
If you don't shut the barn door, the fucking horses will run wild & you'll pay the damages.