One joystick has to exist since there are many videogames where the character is not in focus (barely), thinking of hack and slash with top down camera (the recent diablo 4),the majority of the focus is on where the attacks are going.
In top down bullet hell shooters the player had to aim and shoot in one direction as it walks in another (potentially opposite), so one stick is still needed
Agreed — I'm thinking we'd have just one joystick, to control movement. The second joystick could evolve into some new interface, or devolve into a row of buttons.
PSVR2 already has eye tracking. And unlike the Apple Vision it also has controllers with a stick. Perhaps there are already such games which let you aim with your eyes (assuming you are shooting at something), while you move around with one stick, and the second stick isn't used at all.
In top down bullet hell shooters the player had to aim and shoot in one direction as it walks in another (potentially opposite), so one stick is still needed