I agree but a top player would have been great regardless of eras. You can only play with equipment/competition at hand.Imo, that means they would play as well as necessary to get to the top, irrespective of era.
It is a general statement- whatever (level of skill) it takes to win against whomever I gotta play- not a statement about the measurement of a specific player' proficiency.
The best pros of today are better than the best pros of yesterday were. In all sports.