Federer is the most successful male player of all time in terms of many things, i.e. money earned, visibility and popularity world-wide, number of grand slams won which is the gold standard of tennis greatness, best weeks at number one stats, etc.
How is most successful of all time so different from GOAT?
Money earned? I'd hate that to become the gold standard, because in 10 years someone will make more money. But if you are comparing to someone like Laver, who had to go through things modern players can't conceive of to make money, I agree.
Popularity? I'd hate to go by that either, but yes, Fed is very popular. Visibility is linked to the time we live in, when people all over the world get to see all sorts of matches on the wide-screen TVs with digital quality.
But when it comes to weeks at #1 or most slams, the pros in the 50s and most of the 60s were absolutely screwed in terms of playing slams. Laver's best years were mostly hidden, also Rosewall's, Gonzales' for sure.
I simply say that each era had a few amazing players. There was Kramer and his crew, then the people who played in his troup and eventually rose to the top, first Gonzales, then Rosewall, then Laver.
Then you have the era with Connors, Borg, JMac, Lendl, and so on.
There is some overlap, and you can talk about great rivals in the same era, and how their peaks rise and fall.
That's what we do already with Fed, Nadal, Novak and so forth.
To me what you are doing is like cheating. First you say that you don't believe in a GOAT, then you pretty much declare Fed as the same thing, only swapping "greatest" for "most visible, popular and highest paid".