With partnership-based models, it's not necessarily the case that most of the doctors who owned their practices were necessarily that entrepreneurial. Many probably joined the practice and then became partners after a few years with buy-in and sweat equity. There's some risk and business management involved, but not the same as really doing your own thing. The path was laid out. (Kind of like lawyers at big law firms.)
The real entrepreneurs were the ones who initially founded a practice from scratch. But for some specialties where PE has taken hold, you need a group of people with enough capital to do that, negotiate contracts with hospitals for admitting privileges, wait-out a non-compete from a prior practice, etc. That takes time, and meanwhile, the net share of PE held firms may still increase for a while as other firms continue to sell out.
And of course nobody has sympathy for doctors with student loan debt, but the debt may still have important effects on the economy down the line.
The 80s to 00s doctor years were very good. Now the power is in the hands of the government and huge insurance companies, and to compete with them, you need to be part of a large healthcare provider group, which ends up happening as an employee.
Plus medical school debt and increasing years to become fully practicing like having to do longer residencies and fellowships.
For the same reason that nobody builds out a second set of power lines to compete with an incumbent power utility.
It's capital-intensive, the size of the medical market for the area is fixed, and you'll just be fighting the established practice for it in a zero-sum game.
You can win, but it's going to be way more work for less reward than just finding a PE practice that's hiring/a traditional practice with spare space that's looking for a partner.
Retiring doctors are selling because this lets them cash out their practice for way more than they'd otherwise get for closing it and auctioning off the equipment.
> Why aren't doctors just not selling their practices and taking a more relaxing job running things themselves?
The ones that are selling are the ones exiting the rat race, the downsides aren't affecting them.