I think the picture looks quite different if you look at things like quality of life indicators— and then it's (surprise!) nations like Denmark and Switzerland which top the list. I suspect it would be even more stark if you were able to measure class mobility— the number of people who have at least +x% inflation adjusted net worth over their parents at the same age.

So yeah, it's a little bizarre (and a very US-centric view) to just assume that "success" on a national level and socialist policies are mutually exclusive.