> Doctors aren't paid by the hour.

Not explicitly, but do you think the salary wouldn't change in the medium to long term if the hours changed significantly? Of course, in the short term you can burn out your doctors by making them work longer.

If the supply of doctors wasn’t artificially suppressed as mentioned by comments above, it’s likely that wages would go down. Whether that would make things overall more or less costly isn’t easy to answer.

Doctors are paid in loads of different ways including profit sharing, RVU-based models, and hourly.