Most Western European socialist states have been able to get away with socialism because of a few main attributes
1) They are small
2) They are ethnically homogeneous
3) They are very highly educated
4) They are relatively wealthy to begin with
The countries starting to fail now are the larger ones (Germany and France) who are growing increasingly heterogeneous and poorer due to massive, uncontrolled third world, mostly poor Muslim, immigration. socialist systems are largely rigid, don't scale at all, and are not nearly nimble enough to react to rapidly changing, diverse demographics...