So in 2003, Rafa's first half-year, the top players were a mix of Roger's peers, with Hewitt #1, Safin #3, Ferrero #4, Roger #6, and Roddick #10, intermixed with guys from the previous age cohort (Kuerten, Moya, Costa, Novak), and old Mr Agassi. Some of Roger's peers had been in the top 10 or 20 for two or three years already. Roger himself, who was actually slightly on the side of late-blooming for that time, reached the top 20 in early 2001 and the top 10 in mid-2002, about three years before Rafa. Meaning, Roger was a tad late-blooming, and Rafa very early-blooming, so their prime years overlap more than usual for players of their age difference. Novak was also a bit earlier to bloom, but didn't reach the top 20 until late in 2006 and the top 10 until early-2007, a year that still saw Roger's generation dominating the rankings, with only Rafa (#2) and Mario Ancic (#10) finishing the year in the top 10, among players born 1984 or later. By the time Rafa reached #1 and Novak won his first Slam, both in 2008, most of Roger's better peers were in decline.
So while there are fluctuations and players are different, there are general age-related groupings that travel together to a large extent, in "generational packs" or cohorts.
I mention this in such conversations, because Roger is the lone survivor of his generational cohort, at least among the top 10. Roger finished 2020 at #5; the next highest ranked player who was born in 1983 or earlier was Feliciano Lopez (born the same year as Roger) at #64. To find another born 1979-83 (+/-- 2 years from Roger's 1981) finishing in the top 20, you have to go all the way back to 2016, when good old Dr Ivo finished at #20 at age 37 (he was born in 1979, two years before Roger). To find a second one in the top 10, would be David Ferrer at #7 in 2015; to find someone other than Roger in the year-end top 5, you have to go all the way back to 2013, when Ferrer finished #3.
Another interesting bit: here are the Slam winners from Roger's cohort (1979-83): Roger 20, Safin and Hewitt 2 each, Ferrero and Roddick 1 each. To find any of these guys--all of whom reached #1 and won a Slam before Roger, except for Roddick, who reached #1 before Roger, but won his first Slam, the 2003 US Open, after Roger's first at Wimbledon that year--in the YE top 10, you have to go back to 2010, when Roddick finished #8; to find any in the top 5, you have to go all the way back to 2005, when Roddick and Hewitt were still there.
What does any of this mean? Beats me. But it is interesting. Roger is outlasting his age cohort in a rather astonishing way, and it seems that Rafa and Novak are doing the same. Of their age cohort (let's say 1984-88), the last guy in the top 5 was del Potro in 2018. Murray and Wawrinka were in the top 5 in 2016. Meaning, their cohort has faded as well - and as has even the next generation, the guys born in 1989-93, with the exception of Thiem, who may be better considered "The First Next Genner." A large part of that is obviously because it was/is a very weak group, with only Dimitrov, Raonic, and Nishikori (twice) every finishing in the top 5.
And yes, I think a good part of this anomaly--the longevity of the Holy Trinity--is because they're all just so damn good. Roger was so much better than his peers, and Rafa and Novak are also so much better than their peers. Roger's peers faded quicker, though, while some of Novak and Rafa's peers hung around for a bit (and a few are still around, although almost all have faded).
I find all of this stuff interesting, a fun way to look at tennis trends and history. Despite what you think, I do not use it as a way to rigidly define players or generations. It is a lens, a modality, and yields interesting things to think and talk about.
What it is not is a way for me to try to put Roger in a shinier light. He can do that all on his own. I think your unfortunate tendency to misunderstand me is partially--if not totally--due to your nature as a Rafa Warrior, where you're seemingly always looking for signs of "Rafa offense," and unfortunately sometimes seeing it when it isn't there, at least in my case (I know there are some who are always going after him).
Hey, you do you - but please try to understand where I'm coming from, and more so, where I'm not coming from.