Why are there so many self-employed lawyers and doctors?

[varik]

if they wanted to start their own business.........
they didn't need to invest thousands of dollars and 8-10 years time into college.........

they could have just opened up their own retail store and start selling stuff and providing services.

It's the same concept, just different services.

What is the logic in wasting all that time and money on school if their goal was to be their own boss?