XBox I don't even think has much of a future in the hardware business. With no serious competitor in the stationary business I don't think there's much pressure on Sony to have to take hardware losses any more so they will probably go with something of a more modest upgrade for PS6 which has a fatter profit margin for them day 1. Honestly though even PS5 wasn't that great of an upgrade over PS4 to begin with. Why even bother taking a hardware loss to begin with when you have no direct competitor.
The bottom line is it's all well and good to have hardware that requires $300-$500+ million to be spent and 7-9 years per game in development time to push performance and have the kind of scale traditional big budget games have, but how many studios can even afford to make those games.
GTAVI started development in 2014, it's not even ready to release 10 years later. Now ask yourself about games that are going to aim to have 2-3x greater visual complexity and some decent level of scale to top GTA VI ($500 million budget for the game itself too) ... like it becomes almost silly to think what that game would have to be to dramatically outpace GTA VI. $1 billion budget just for the game itself? Another 10+ year dev cycle? Who wants to finance that?
You're not even going to see traditional console transitions anymore the way it used to be, cross-gen period is already 3-4 years now, that will become even longer to the point where generations don't even feel distinct at all because developers are already drowning trying to make games for existing hardware.