I think it is a mix of things that make 5-10 years sound reasonable to me. Part of it is the equipment setup and hardware requirements make it almost a gaming hobbiest attraction still. (although I have not set up a quest or reviewed the recommend specs)

The comparison consumer-ready technology would be an iPhone or a Nintendo Switch which are sort of out-of-the-box experiences mainstream consumers are quickly getting used to.

The Oculus Quest is an out-of-the-box experience. Oculus is aiming for mainsteam market with this. Maybe you're confusing the Quest (standalone) with the Rift S (wired).

As soon as you unbox the Quest you're ready for the onboarding process (which is quite enjoyable btw). No PC or additional hardware required.

There is no equipment setup or hardware requirements. The Quest is a VR console that works out of the box. Everything works on the headset itself, so there's no need to set up the IR beacons that the other headsets require.