At present, only a very small percentage of Steam users have the necessary requirements to play with Half-Life: Alyx.
Half-Life: Alyx could mark the great return for the Valve series, but at present, the vast majority of Steam users do not have the necessary requirements to play with it.
By controlling the Steam database it is, in fact, possible to notice that only 37% of the players have a video card capable of supporting VR, but the percentage goes down a lot when you check the number of viewer owners: 0.38% has an Oculus Rift, 0.34% of an HTC Vive.
It seems shortly that Valve counts on the fact that Half-Life: Alyx can be the killer application that will allow selling the Index and the other VR viewers: a decidedly ambitious bet.
Of course, we must also consider that in terms of system requirements, Half-Life: Alyx indicates an NVIDIA GeForce GTX 1060 video card, which is the most common video platform user.
In short, the will to sell the game to as many players as possible is all there, after which it is clear that with a mid-range GPU one can never hope to achieve the visual quality admired in the ad trailer.