No, I mean if Smash Bros. fans didn't invent the word "main" in reference to your favorite character, then does that mean Nintend did?
I assumed he meant it came from other fans, that it's not SSB-exclusive. It's just a fighting game phrase. I could be wrong, though.
I was best in SSBM as: Luigi, Captain Falcon, Mario, Jiggypuff and Kirby. As far as Brawl, I'll probably be using Wario and Sonic a lot so hopefully I get good with them. Snake too, actually. I sometimes play with rules to the extantr of "winner keeps character, loser has to change". It forces character change and it's kind of fun when my friends would pick their best character and then lose and have to change.