So Novak style is grinding him down, and he'll win more 4 slams, post injury Nadal whose style doesn't grind him down at all(lol) and is 1 year older will win the same 4 slams. Seems legit.
you do realize that clay courts do not grind down the knees very much at all? Nadal PLAYS HIS BEST ON CLAY AT ROLAND GARROS. he could literally have knee surgery and probably still compete at the French Open. UNFORTUNATELY for Novak Djokovic, he plays his best ON HARD COURT. at the Australian Open. if Novak's knees decline (which you seriously don't think he'll face any problem after, like, 4 slams, which was my prediction he'll win?) it will be very VERY tough for him to win on a hard court that is rough on the knees.
Nadal in a way is fortunate he won SO much early, his favorite tournament is the easiest on the body of any tourn in the world.
you are not thinking straight if you think Djokovic is likely to win 4 + more hard court slams or whatever. the reality is that if Nadal is still healthy it would not be strange or surprising if he won 3 more Roland Garros's and a WImbledon or something similar.
once again, both players are likely to decrease quality of knees and physical well being dramatically in the next few years (NADAL has run so much in his career, BUT LOOK AT Djokovic's SLIDING on hard courts), but it all has to do with their best tournament's surface. certainly Nadal even with worse knees can win at Roland Garros a few years from now because the surface is relatively gentle. the Australian Open and US Open on the other hand... (Novak's best tournamnets)
I mean for gods sake did you miss all the talk about how rough the Australian Open was on players knees this year? miss what happened to Bryan Baker? the reality is that Novak will not be able to maintain the knees for THAT many year. the next 2, 3 years maybe. if you think he will win THAT many more than 10 or so then you are being delusional and have lost a grasp on the difficulty it takes to win at this level
and if you fail to recognize that Nadal will be the mass favorite to win Roland Garros probably until he is 30, and a big favorite at Wimbledon too, then you are kidding yourself.
once again it all revolves around SURFACE type. at 27/28 it begins to be much harder to keep the body healthy and win on hard courts. Federer is not the norm despite what the tennis community seems to want everyone to think with their constant tirading of 'tennis is becoming an older players game'
P.S. however it obviously should be noted that these are predictions assuming the players stay relatively healthy. tennis is unpredictable, any of them could in ONE random tournament have a career ending injury. and it's certainly not just Nadal, despite him getting a lot of attention for obvious reasons with his big break from the game. I cannot bring up enough Novak's sliding on hard courts. that is extremely tough on the legs