I have interns with higher salaries and more purchasing power than senior devs in Europe.

It's remarkable what little you consider "proper".

I doubt it comes out so much ahead if you factor in the vacation days, the sick leave, the healthcare, and the education costs.

Enough money to pay for housing and food and save up for the future and a nice vacation every year, with no chance medical bankruptcy.

Having a proper salary doesn't mean they would not appreciate getting even more money.

Who wouldn't?