Currently Online 
Feels a tad bit early to be predicting what could be a decade (or more) long console generation. Depends fully on whether Sony gives their player base good exclusives, at what rate, and how this whole chip fiasco settles out (though being that all of this is happening without even the War in Taiwan having broken out… um yeah not good).
At a $1200USD initial price tag that goes up to e.g. $1800USD by the end of an 8 year long generation, then yeah it’ll certainly be a struggle to top 50M. But if the price stays somewhat near to $1200USD for a 12 year generation? Then perhaps we’d be looking at closer to 80-90M.
That said: Just for grins and giggles, I’ll give a swing and say PS6 settles somewhere in the 45-55M region assuming an 8ish year console generation.
