The Quest is pretty limited in hardware. The article mentions they use both Quest 2 and Quest 3; the Quest 2 is a $250 device that runs on a 5 year old mobile chip (about the same as the one in the Galaxy S20 Plus). The Quest 3 is much better (about on the level of a $500 phone), but they might just use the same games on both.

And in VR/AR low latency and high framerate are much more important than visual fidelity. Your brain just kind of accepts those low fidelity representations, but reacts very badly to latency spikes or frame drops.