The value proposition of PP is usually not there unless you have an "in."
You can get a 100k+ signing bonus from a rural hospital while still in training and 75th percentile income and do this for a few years until your debts are paid and you've got a decent nest egg growing then start looking for something in a better area for less if you want. It's unclear how long this will even be an option, so the adage is make hay while the sun shines.
Compare this to a 300s partnership track job, potentially end up doing huge amounts of work without any extra pay, then maybe if you're really lucky and economic conditions are still favorable and there hasn't been a buy-out, be presented with an opportunity for an astronomical buy-in in 3 years. And this will likely be in some sort of tiered ownership structure where you are still low man on the totem pole. It's a huge gamble and it only makes sense if the potential partner income is well into the 7 figures, which is rare. I have seen multispecialty groups where partner income after split with radiology or whatever basically ends up at 75th percentile MGMA. So at that point, why? Take the employed job, paid benefits and PTO, forego the partner meetings, overhead, and debt obligations. Not a hard decision for anyone without but the most extreme risk tolerant.
It baffles me when PP offer a low salary, high workload, crappy benefits, zero autonomy (being an associate), driving all over the place to cover multiple machines, and minimal PTO (there was a point I had ZERO) with a vague carrot of "possible" partnership and are shocked that people turn it down and go "work for a hospital" instead. I have personally heard these conversations of truly not getting why offers keep getting turned down, and it's amazing. They literally are that out of touch that they are unable to understand that their amazing life as a partner with 1.5M income and ability to unilaterally decide clinic operations and schedule is not what is being presented to the candidate. PP is so awesome! Why would anyone not want this?!