VR failed to take off? by what metric
This is the standard that was implemented into cards for a couple years in the hopes it would result in headsets that connected to a computer with single cable. Compatible headsets never materialized so the port disappeared
And we also only have a few high budget/tier games that are made for VR (arguably, only HL Alyx)
The Quest isn't really relevant here, and it's also extremely heavily subsidized.
It is by no means mainstream.