Fair, but I mostly meant people who really experienced and remembered it. Aged around 50+ (like Trump).

So forgetting that… Not a big deal. Remembering its old name first… OK, not remembering the current name after the old one - weird. And, finally, doing that constantly in many occasions, sign of mental problems.

I don’t know, I would say after the fall of the Soviet Union its renaming was fairly common knowledge if you lived through that (even outside the former Soviet States)