The claim is that "European public health insurance is commonly contingent on employment", not "European public health insurance monthly payments vary based on

The claim is that "European public health insurance is commonly contingent on employment", not "European public health insurance monthly payments vary based on employment status." The only way you could end up paying more is if you previously made an average amount of money, have a lot of savings, but now make nothing. Normally this is called "retirement" and if you didn't save enough for it, you don't do it.