"or specialist you have to start your own business, too? Also known as a practise?"
The number of practicing dermatologiests strictly limited to an amount determined by a council of dermatologists via the AMA. Programmers have nothing remotely similar.
This applies to all doctors, when you can artificially limit your supply, of course salaries are high, you make sure of it. If everyone who was qualified to be a doctor -- i.e. residents who should already be but don't have that magic piece of paper --, was made a doctor automatically after X years of residency, wages would be no higher than programmers.
The number of practicing dermatologiests strictly limited to an amount determined by a council of dermatologists via the AMA. Programmers have nothing remotely similar.