For me the issue is Djokovic and Nadal understandably declining noticeably with age, but still continuing to rack up grand slam titles at an insane rate, or in some cases actually speeding up. Djokovic has won 10 grand slams in his 30s compared to 12 in his 20s. While he is still of course a phenomenal player nowadays, I think he was clearly a better player during his mid to late 20s (I don't think it's close there), with his absolute peak level in 2011 (even ahead of 2015 which was statistically a better season for him).
Similarly Nadal's absolute peak level was in 2008 closely followed by 2010. The 25 year old Nadal that lost to Djokovic in the 2012 Australian Open final was clearly (to me) and understandably a far better player than the 35 year old Nadal that won the title in Melbourne last year.
That does highlight to me that the level of competition has simply significantly weakened. I was saying previously that last year when I stumbled across a YouTube documentary re the wonderfully exciting 1992 US Open, that I strongly doubted that there was better depth in the ATP top 100 in 2022 than there was 30 years earlier in back in 1992, in-fact I'd say very much the opposite.
I do think that generally the 80s born players / supporting cast were ultimately just far better than the 90s born successors (they certainly played with more variety as more members of the 90s group play bland academy style tennis). What hammered that home to me, was the fact that it took the players born in the 90s seemingly an eternity to overtake the likes of Ferrer and Berdych.
The top 100 today would absolutely shit on the top 100 in 1992. It might get close in the 1-20 range but comparing the 30-100 ranked players between the two groups i'd take the current generation everytime.
Just for fun i'll compare the lower seeds at a couple random tournaments. Let's take 1995 us open and 2020 Australian open:
Thing is back then they only had 16 seeds as opposed to 32 now
So for the seeds 10 to 16 we have:
Wayne Ferreira (first round)
Sergi Bruguera (second round)
Richard Krajicek (third round)
Marc Rosset (fourth round)
Jim Courier (semifinalist)
Todd Martin (fourth round)
Andrei Medvedev (second round)
Gaël Monfils (fourth round)
David Goffin (third round)
Fabio Fognini (fourth round)
Denis Shapovalov (first round)
Diego Schwartzman (fourth round)
Stan Wawrinka (quarterfinals)
Karen Khachanov (third round)
I think the oldies take 1 or 2 matches, 3 at best.