One thing for sure; only one pitcher can pitch at a time, and only one batter can bat at the same time.
Comparing one era in a sport to another is good fun, but the real measure of a player's greatness is who remembers him after the game changes and the current heroes change.
How many kids today can identify which sport George Mikan played, let alone which team he played for?
How about Sam Huff? (I would have said Ray Nitzche, but I can't spell his name.)
Babe Ruth will be a legend for a long time, and has been a legend for a long time already. And that's because he was the dominant player of his time. There is no house that Jordan built. Comparing a mortal like Barry Bonds to Babe Ruth might keep people busy for a while, but it's not fair to Barry Bonds.