AI is not the best 76er. Come now.
best, no, but statistically he probably rates higher than the better players as a Sixer.
I mean you could easily argue the "best" Sixer is Hal Greer who is the all time leader in games, minutes, FG's, points, fouls, and who is 2nd in assists, 6th in rebounds, 4th in win shares, etc. He is in the HOF and was a key member of a title team as well, so it wasn't like he was just some role player.
Now sure, Wilt, Moses, Dr. J, Sir Charles are likely all better players than Iverson (and certainly are all better than Greer), but none of those guys had the length of time as a Sixer as Iverson did. And it isn't like Iverson wasn't a league MVP, scoring champ, etc.
Think of it this way, Garnett was clearly a better player than Pierce throughout their careers, but Pierce was a much better Celtic historically speaking.