Yep. That's a good argument. I happen to think that Bruce was the best ever to play that position and OJ probably wasn't to play his. But OJ may have been a better player. Bruce did it a lot longer.
It's kind of like saying what was the best band of all time. You really have to consider the individual songs, full albums, just the music, the lyrics, performance, longevity, the very best songs or albums. Did they have many bad ones. Etc.
In that respect, maybe Bruce was better. But when OJ was at his very best he was better than Bruce at his very best. Tough to say. Pure talent and ability I would say OJ.