Re: how many slams do the following playing have in them?
A precise numerical forecast is pointless, but be mindful all top 4 are already beyond the best tennis age. Statistically the most likely age to win a slam is 23, only a small fraction of slam titles are won after the age of 26.
Wwe may be close to the end of an era, even though it doesn't feel that way yet. I doubt Federer, Nadal, Djokovic and Murray will win another 10 slams combined.
Current sanyaku ranked players:
Yokozuna: Roger Federer (Dai-Y), Novak Djokovic (Dai-Y), Andy Murray [Rafael Nadal is an inactive Dai-Yokozuna]
Ozeki: Stan Wawrinka (kadoban)
Sekiwake: Tomas Berdych (ex-Ozeki), Milos Raonic
Active ex-sanyaku-ranked players
Ozeki: Del Potro, Ferrer. Sekiwake: Tsonga, Baghdatis, Haas, Raonic, Nishikori, Gasquet. Komusubi: Robredo, Ginepri, Gasquet, Verdasco, Melzer, Monfils, Youzhny, Janowicz, Dimitrov, Gulbis, Kyrgios, Thiem.