Of course there is something to what you're saying but I think you're making it too black and white and I think that's probably because you want to defend Federer's legacy against those of Nadal and Djokovic. I'm not really concerned with goat debates.
It's the second paragraph with which I most strongly disagree. I think that the top 100 tells us much more about peak age than does the top 10. I also think it's very clear that the peak age has shifted upwards by a few years. Not by as much as some said, but by a few years. This is a phenomenon that goes well beyond men's tennis. In the women's event, for example, 12 of the 16 players so far through to round 3 are 25 or older. This is a very clear change from the past patterns.
Teenagers winning slams and making the upper echelons of the rankings was fairly common in the 80s. It has become much harder for younger players than it was. Of the top 100, only four (Alcaraz, Rune, Shelton, and Musetti - who turns 21 on 3 March) are aged 20 or younger and only four are aged 21. So, 92 of the top 100 are 22 or older. This is a change from the past. Actually, teenagers no longer being competitive is a change that happened long ago - as early as the 1990s - and has been fairly stable since then. So, yes, the mean age has dropped a bit since 2020 but it is still much higher than it was in the 1980s and somewhat higher than in the 1990s or 2000s. Players in their mid 20s have indeed become dominant again, but players younger than that are still only occasionally competitive. Alcaraz and Rune have done very well indeed, but we saw in their absence (plus that of Sinner) that the field at the NextGen finals was actually considerably weaker than in the previous few years. Looking at the young players in the rankings, it doesn't seem as though there is a huge bumper crop coming through below the top 100, either. At older ages, there have been plenty of players doing decently well in their early 30s in recent years - even last year, Cilic made a Roland Garros semi (for the first time). It's not just the big three/four/five.
I'm not denying that there was a weak generation of players. I'm denying that that's
all there is to it. Of course, it's inevitable that when a group of players goes on a long time, there will then seem to be a marked shift to a younger generation, because the players who are by then middle aged haven't become as great as they could have done, and so there's a power vacuum. The same thing happened in the early 2000s. The real test will be in a few years, when the likes of Medvedev et al get nearer to 30, or into their 30s, to see whether they can be competitive or not.
So, rather than spending more time debating this now, why don't we just leave it a few years and see what happens? I'll try to keep updating this thread. It's been a labour of love for a few years now, so I imagine I'll keep going.