Aabye5
G.O.A.T.
There are a combination of factors: matches contested, competitiveness and player achievements on the year. Agassi and Federer may have played the most, but Nadal ended the year #2 and challenged Federer more than Agassi did, with three of their four matches being routine. If sheer matches played are the only factor then Ferrer was as much Nadal's rival as Djokovic was in 2013.
Is Rafa or Nole the biggest rival of Alcaraz? Are they the biggest rival of FAA or Sinner or Ruud?
I know you know the history, but the state of mind was different. In 2004, Federer beat his 3 most important contemporaries in 3 Slam finals - Marat, Lleyton, Andy. If Tsitsipas had beaten Med at the AO, Ber at W, and Zed at the USO in 2021, that is perhaps the only way the size of this shift can be understood in today's terms.
I'm not trying to lecture you, just reminding you that in 2004 this was mind-blowing!
Yes, there was talk about the new wunderkid Rafa (as there would be talk about Carlitos, even if Tsitsipas had won 3 Slams in 2021). But it was still told in terms of Federer. After his tear in 2004, Roger was missing one Slam and he turned his attention to Roland Garros. The wunderkid stamped his dominance on the tournament by defeating...Fed.
Rafa was good, very very good. But mainly on clay. Or, at least, that was what people thought.