It works when everyone is Scandinavian. But watch what happens now. They will develop a non-working class and things will change. Socialism works when everyone’s inclination is to work hard and pull their own weight.
It never works when people have different levels of personal production. Those who work less get more for doing nothing. Those who work more, see it and stop working for others, and start working only for their selves. A good example are the Russian collective farms vs. the personal gardens. Read Anna Karenina.
Also, many of these Euro-countries are not really socialist - means of production are not owned by the govt (except maybe for British North Sea oil and Norway’s oil). They tax to create a welfare state to prevent unrest. So taxes are high for that but because it is spent on people that are pretty much all related to each other it does not sting as much to pay that much.