The important Wawrinka has had on the way things currently stand; damage he has done to Djokovic

You can play the "what if?" game with considerable more gravitas if you restrict the parameters to ATG's:

Without Nadal, Fed would be at 27 slams
Without Djokovic, Fed would be at 24 slams
Without Nadal, Djoker would be at 20 slams
Without Djokovic, Nadal would be at 23 slams

etc etc. etc. etc...
For sure, but that is also expected. ATGs taking slams away from other ATGs. A player like Wawrinka making such a big difference to any of the GOATs, is the far more shocking thing.