The biggest difference is that housing is a lot more expensive in western cities - it is likely that even a modest 2-room (1-bedroom) apartment in a major city like Amsterdam would cost the majority of that wage to rent (and we're not talking about just students, but older people who can't get better jobs).

You say it like you just grabbed a random example, but Amsterdam is one of the most expensive places to rent in NL. It's also generally not at all representative for the Netherlands as a whole.

Ok, you may replace it with London, Paris, Zürich, Munich, Copenhagen, Stockholm and probably a dozen other western european cities (not to mention major American cities, which are sometimes even more extreme).