I'm not sure you're getting your own point. If you're a truly great player, and stay fit and healthy, and you have not much of anyone to challenge you, you're getting a bit of a free ride, in this era, if you're there to take it. Credit to Novak that he is. He didn't have to be asked twice to take a bit of a gift into the SFs of the YEC...and run with it. I have said many times that a mark of greatness is opportunism. See a window and barge through it. But I don't agree it takes a truly great player to do what he's doing now. It's takes a great player who remains fit and hungry. He is that, and I credit him. But lack of significant competition is a factor. You said so above.
My point is that BOTH are true, and you just want to emphasize the part that diminishes his accomplishments. Kind of predictable, but it is unfortunate that you don't take the middle ground when it is offered, or that you can't acknowledge Novak's greatness without qualifications.
As for the bold part, if that is the case, why has no one but truly great players EVER had seasons like he had in 2023? Why don't we EVER see less than truly great players dominate the tour for more than partial seasons? Well, for one, that would make them truly great.
Even Stanimal at his best was only truly Stanimal for short spells, even just three tournaments. He was really good there for half a dozen years or so, but it was only in those key moments - and scattered over a few years - that he reached "the level."
That's one of the things that differentiates the true greats from lesser players: the greats maintain their greatness; they are more consistent, and have entire years of greatness. Lesser players tend to come in two varieties on a spectrum: the Stanimals who flash moments of greatness but don't sustain it, and the Ferrers who are consistently very good but never really great. Neither of those types of players every put together whole years like Novak's. A Stan or Del Potro or Safin will reach that level for short periods, but then fall back - and never for a full year, at least at Novak's current level.
Here's a fun little stat that PEP is good for.
Biggest Outlier Seasons by PEP - Differential Between Best and 2nd Best Year (Age 30 or over)
+23 Andy Murray 2016 (54)
+19 John McEnroe 1984 (65)
+18 Guillermo Vilas 1977 (44)
+16 Marcelo Rios 1998 (26)
+14 Thomas Muster 1995 (32)
+13 Mats Wilander 1988 (47)
+12 Marat Safin 2000 (29)
+11 Andy Roddick 2003 (31)
+10 Ilie Nastase 1973 (41)
Rod Laver's 1969 (78) was +35 over 1970, but he had several seasons in the 1960s that were a lot closer (I'm developing PEP for pre-Open seasons).
So you could argue that Murray's 2016 was the biggest fluke season. he had other really good seasons, but not above 31. McEnroe's 1984 was so good that it made his other seasons look relatively pedestrian, but he had some other great years - just nothing close to '84.