> Healthcare demonstrates the other extreme of the problem in my experience, where entrance to the field is gatekept by the medical education system to ensure that there's not an over supply of professionals that would put downward pressure on existing salaries.

That's not a bad thing (to a point) when the entry-level qualification takes a massive amount of time, intense effort, and money to get; it's very important that they manage it so there's no oversupply. If you don't, then you'll have disasters like US legal education has been.