5 years ago things looked bleak for S&D but then won in many areas looked bleak like Spain and Germany. Yeah in trouble in both now but I think Europe is now in state where winning re-election tough although parties on right seem to have better record. I do think as has been case since 2000, parties on right will win more than parties on left but parties on left still win occasionally.
It comes and goes, mostly the reverse of the angloamericans.
The discontinuity is because continental europe weathered the 1973 oil shock better than America or Britain, so they largerly saw no change in power.
So when a crisis hits they flip, but in opposite directions, it's rare to have France and America in alignment for too long.