This is a good point. And it actually ties in with the hostage joke further up in the discussion.

In the US at least (I can't speak to other countries), college and med school are very expensive, and a lot of medical professionals are surely carrying student loan debt and can't afford to lose their jobs and be without income for a while. It also makes any sort of kickback of payoffs much more tempting. Not only that, but doctors tend to come from the middle and upper middle classes, aka the PMC, and status consciousness and conformity are deeply ingrained.

So you have people who are conformist by selection, to whom status is very important, and who on top of that are often paying off student loans and terrified of losing their income. It is indeed a kind of hostage situation, even if many of the chains are in their minds.