Hardly "serfdom" when it is your choice. Following on from the tortured logic, you would have to wonder at the intelligence of those who voluntarily contracted to become "serfs."
Yes it is expensive, but so are many things in life. Private schooling for just the 5 years of secondary education often far exceeds the cost of integrated flight training. University fees are rising to a level that would rival the cost of a modular CPL/IR course. Don't even begin to ask Americans about the costs of college education, and there, that level of education is a pre-requisite for a career as an airline pilot.
Nobody forces you into this career, and yes it is usually very expensive indeed. If you are being forced by someone, then might be some merit in the argument, otherwise it is moot.