You can mass produce anything, but it has a cost.
I have the impression that some people imagine that you can produce now 10x more doctors at the same cost that you were producing one doctor 10 years ago. Mostly because some tasks (even programming) got many times "more efficient" I feel people transfer to easy to other topics.
Even worse, education expenditure is decreasing for many countries! (see some examples: https://ourworldindata.org/grapher/education-spending?tab=li...)
There have always been a lot of incompetent and even dangerous doctors. It's just that patients weren't aware of this and tended to trust their doctor even when the actual care quality was terrible.
Earlier you just need to find a doctor and they were probably good. Now you have to take your luck with many till you find a good one (if you are still alive by then)..
I don't know why people think that they can mass produce competence..