I live in Belgium, we earn quite a lot less on average indeed. However why would we need so much money? We can go to hospital, or even 20 times visit a dentist for that matter, without expensive insurance and without the fear of bankruptcy. We can have kids without fear of not being able to pay kintergarten.
Kindergarten is free in the US. Also the vast majority of people pay a relatively small amount of their income for health insurance (and of course it’s free for 65+ who are the primary consumers).
Also: In Belgium, can you really go to the dentist 20 times? Is there any good reason to allow this in a public healthcare system? If the barrier to entry for healthcare services is very low, then there must be (1) a lot of abuse... or (2) long waiting times... or (3) very high taxes. My guess in Belgium: A combination of (2) and (3).