Also have to account that there were only 12 NBA teams then Wilt played which meant he was competing against the top 140 players in the world as opposed to the top 450 players in the world today
What? Smaller league means better players for each team
if all else is equal. But all else is not equal. Do you really think that the best "140 players in the world" were in the NBA then? Mutombo, Hakeem, Duncan (Virgin Islands, he's playing soccer then), Dirk, Ginobli, Parker, Gasol, Yao, Petrovic, Stojakovic, Greek Freak, Nash, Jokic, Nurkic, Mirotic, Embiid, Wiggins, Ewing, Bol, Kanter, etc... In fact, without guys like Wilt and Russell making basketball popular (which is a service they get little credit for), even someone like Shaq might not have decided to play - recall he grew up an Army brat and lived in Germany and Texas (maybe he ends up playing football). Just this year, there were 113 international players from 41 countries and territories.
Now add in that NBA players made little salary back in the day - for example, Dave Cowens moonlighted as a cab driver in the 1970s - which means that a smaller % of US people sought out the NBA. Today's huge salaries lure in everyone with the requisite height and athleticism to at least try to make it.
Not to mention that a higher % of the league is in great physical shape - nutrition, training, and injury recovery. Would someone like Kareem (noted health nut) have such a comparative advantage in these areas against the modern NBA? Likely not.