Except... that's not true.
There are a ton of ways to gauge economic performance but in the interest of not spending hours writing this and siting sources i'm going to choose the ratio of those employed versus the total population of a country as evidence that quite a few European countries are doing at least reasonably well economically speaking. I am choosing this number over unemployment rate as it is much harder to fudge and doesnt exclude parts of the population like in the US where people who are not working and havent looked for work in the last 4 weeks are not included.
Here is my source data: https://en.m.wikipedia.org/wik...
In going over the data you will find the US at a ratio of 67.4 which is not bad. On the other hand though, you will find a ton of European countries (outside of the South of course) and Canada with rates in the 70s which strongly suggests they are at least doing alright economically speaking (not to mention it contradicts the American conservative "wisdom" that socialism disincentivizes people from working)
There are a ton of metrics that can be brought to bare when gauging a country's economic prosperity, some will show the US as top dog economically speaking and others a bit less so (like the fact that Canada has a more rebust middle class then us). In using this one single point, however, I do feel i've established that quite a few countries more socialist then us are doing at least alright economically speaking.