There are 9 big hardcourt tournaments.Six Masters 1000,2 Majors and 1 WTF.
Djokovic has already won 6 of those at least once.The only ones missing are Cincinatti,US Open and Shanghai.
Can he win those 3 at least once before he retire?
I personally don't think he can.I am optimistic enough that he can pull 1 US Open,and maybe one of the Masters 1000,but probably not both.
Incidentally,the only of those tournaments Federer doesn't have is Paris.
Opinionated people always make me laugh. You start off strong by quoting facts, but end weak in your sports commentary by merely stating an unsupported opinion.
Here's what a supported opinion looks like:
I think he will win the remaining ones because:
1) hard courts are his best surface.
2) he's been a semifinalist and finalist several times at USO at a young age.
3) he is currently dominating hard courts and has proven himself
4) why the heck couldn't he win two second rate 1000 tournaments if he focuses on them? duh..
5) time is on his side.
6) he feels dominate on hard courts (tennis is very much a mental game).
7) etc etc, i could go on.