Lior:
Regarding your first paragraph, while it is possible, it is highly unlikely that there are 20 or so missing rishonim who all hold ??????. Also, if you think that majority/minority is irrelevant (since there might be other rishonim that we don’t have), why did you begin this thread by saying:
“we cannot rely on the other minority shittos that permit a Jew to not become shikur on Purim”?
As for your second paragraph, the term “drunk” is very vague. I don’t think there is any rishon or acharon who said not to drink at all. But there are many levels between that and ?????? ?? ???. Since I’m not sure exactly what level you are asserting was the accepted practice, I can’t really respond; all I can say is that I have heard from people that in Europe it was a minority who got drunk.