The Big 3 and Beyond

Fed, Rafa, Djoko, (and maybe Murray?), The Big 3 have dominated the game like an aggressive, hungry top for the past twenty years.  With little sign that these legends are slowing down and fuelled by their desire to cement themselves as the stand-alone GOAT, how much longer is the tennis world going to enjoy this trifecta of champions?  How have they gotten there?  How many more Rolex watches do they need?  Is Andy Murray part of this equation or is this only a three variable algebraic expression? (Andy, chime in and let us know what you think!).
And what about beyond the horizon, when the sun ultimately sets on the careers of these three tennis giants?  Who among the next gen of players is thirsty and driven enough to dare and emulate their success?  Zverev?  Thiem?  Tsitsipas?  And what about our Canadian contenders: Shapovalov and Auger-Aliassime?  What place are they ready to carve out for themselves in the tennis history books?  Jason and Aldwin get up in all o' dat and more as they dive into some deep sea big three analysis.