> But four of those years involve studying generally unrelated topics like any other college degree despite medicine effectively being a trade.

There's a lot of value in knowing about more than just one thing. Anyone leaving their university with a degree should have at least some exposure to topics outside of the field they want to work in. People are more than just their jobs, having a well rounded education is useful, and matters outside of the field of medicine still have real impacts on the lives of doctors.

I'd certainly feel better about going to a doctor who has a reasonable baseline understanding of the rest of the world outside of his work. You could argue that people looking to become doctors should able to avoid some percentage of the other classes they're forced to take, but doctors can often pick up some relevant credits while still fulfilling those requirements too.