I agree some drops can happen suddenly and very quickly.
It doesn’t have to be much, but a little bit here and there and also if the team is struggling (as it’s a team game), the difference can be clear as day.
Lampard said he approached every pre-season when he entered his 30’s as potentially his last in football. Of course, he was never a great athlete and he always worked on these things, so he’s one who was always aware. And intelligent.
Torres came back from WC10 looking like he’s lost quite a bit. And we know the reasons why now, he sacrificed part of his health to be at that tournament and that’s his absolute right. But I remember feeling early in that 10/11 season like we’re not watching the same player anymore.
There are cases though of players looking like they might be finished, but then go on to reinvent themselves a little bit. Perhaps not at the very top level, but still at a good to very good level. Aubameyang is a little bit like that, he’s a very good athlete though, so that helps.
It can be a change of mental approach, appreciating the time they have left more than ever, being more humble, experience they gathered, different individual training and how they live off the pitch, tweaking some things, etc.
Benzema is a good example of that, when you see his body today and a good few years ago, he looks lean and hungry. The post-Ronaldo years at Real, that was when he went to a completely new level, although the big time he missed at international football probably saved him for logevity.
It was noticeable wih Robben for example. A bit weird but it felt like he was better in his 30’s than when he “had to be” at his peak.