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: Rafael Nadal (Dai-Y), Andy Murray, Novak Djokovic (Dai-Y), Roger Federer (Dai-Y)
Ozeki: Stan Wawrinka
Komusubi: Milos Raonic (ex-Sekiwake), Dominic Thiem, Kei Nishikori (ex-Sekiwake)
Active ex-sanyaku-ranked players
Ozeki: Berdych, Cilic, Del Potro, Ferrer. Sekiwake: Baghdatis, Haas, Gasquet, Tsonga. Komusubi: Dimitrov, Gulbis, Janowicz, Kyrgios, Melzer, Pouille, Robredo, Verdasco, Youzhny.