A rav I’m close to told me that back in Europe the bare minimum for being called a gaon was to know all of shas rashi/tosfos baal peh.
The term seems to pretty loosely be thrown around today which tends to cheapen it. I’ve seen a chaver knesset who has been referred to as “harav ######## shlita” Now this individual may very well have some sort of smicha and I’m sure he learns when he has the chance but the fact of the matter is what capacity does he function at day to day, or as he ever functioned at to really fill the description of a rav? I’m personally unaware of it (thought could be I’m just ignorant of his full situation) but for me it seems unfair compared to those who are in actual rabbanus