I thought the stats were that the majority of new attending were being hired as employees, and private practices are being bought out by insurers/hospitals/private equity groups
That is the trend, this is true. As i have said above, if you just want to be a "job", someone will make money off of you gladly.
Almost no medical students, and sadly most residents, have absolutely any idea how money is generated in medicine. Sure they understand that patients=money, but not in a practical sense. There are lots of great threads in the resident/attending forums that spell this out in detail, but generally revenue comes from billing for procedures and visits (tiered into E&M codes). Even if the hospital owns your group, it is still set up as a separate business entity for lots of tax/financial reasons. The economics remain the same.
Take my specialty for example, emergency medicine (a shift specialty). Every patient I see has a chart that is coded from a level 3-5 based on severity of complain, and the level of documentation I provide. We can also bill for "critical care time" which pays very well, and for a variety of procedures that we do. The best paying things are often the "fluff" stuff, like placing your own splints. Splints pay well. All of that gets added up and billed the patients insurance company, which pays varying amounts for all of those things based on lots of factors. The type of insurance your patients have is called "payer mix", and it is a huge deal. Lots of young employed families with private insurance = GOLDMINE. Lots of medicaid/no pay = losing money (generally if your payer mix is over 35% medicaid/no pay, the hospital will need to subsidize the group to break even). The other factor is volume, the more charts you fill out and bill for, the more money you make. Low volume places are also losers, and often need to be subsidized.
All that money doesn't collect itself, and there is a cost of doing business. You need a billing company to keep up with all the individual insurance requirements, and a collecting company to actually get the money from people. You need med-mal coverage, health insurance coverage, disability, 401k. If your specialty needs office space, there is a cost of that. You will need ancillary staff, techs, medical assistance, front office staff, etc. How many you need of those vary by specialty, ER needs very little because we don't work in an office. You add up all the revenue from the patients, subtract the costs, and you get what's left over as profit.
That profit can be divided up in many ways. If you group is equal partner, everyone gets their share. If your "group" has a core of equal partners, and many doc's they just employ at a hourly rate, then they keep the extra profits and you get none of it. If your group is owned by the hospital, they keep the money. There are many different business arrangements, but you can see the potential for taking advantage of "new attendings who just want to be employees"
Now, the reason I have written all of this stuff (and trust me, it is waaaaay more complicated when you start talking about hospital contracts and such) is to demonstrate that ALL of this business is going on every day behind the scenes of every specialty. There are parties involved who have set up the machinery, and have the economy of scale, to collect the revenue, and would gladly "hire" you for 250K a year, bill 500k a year in revenue from your work, pay the 50k in expenses, and keep the 200k in profits for themselves.
There is absolutely nothing wrong with being employed, it has a lot of stability, and a lot of physicians just don't want to think about the business stuff.
Being employed has lots of perks; most will pay for your med-mal, 401k, no worries about billing or collecting, you get paid every month even if the hospital didn't. It is VERY important that you are educated about the financial realities of your specialty, so that you can negotiate a favorable contract. This means that you need to find out how much you are actually worth.