Why has boxing regressed when every other sport in the world has advanced?

No, it´s not the only....you had the club wolrd games too....Santos won it destroying Benfica and Milan....
WC was the best way to test who were the best internationally, it was !

Puskas said "the best player of All Time is Di Stefano, because I don´t rate Pelé. Simply because Pelé is above all." Puskas said that !!!! :deal
This quote is in the Santos Museum to everyone see.

The best don´t always win in Boxing too.....but even so we should rate higher who win than who doesn´t win Junior.

You mentioned only ATG players.......if you ask to all of them and to all of the people who saw Pelé in action.....I´m pretty sure 90% of them will say "Pelé is the GOAT" :conf (expect Eusébio, he is a hater)

We rate some fighters using this kind of arguments as well, you know that....