VR is a totally, totally different, very complex and extremely demanding technology. Beyond having to physically drive two (in this example 8K) displays the system has to be able to render the content at at least 90fps baseline (there are technologies to help work around this, but fundamentally they have serious flaws and if you want a good experience you need at least 90 real fps in many titles), AND you have a tremendous overhead with the stereoscopic rendering (assume your title will require 3X the power JUST to make it run stereoscopically), PLUS you need to render a wider FOV than with a traditional display, AND you need to render way, way out beyond the visual FOV all the time anyway so that when a person turns their head there is enough of the scene pre-rendered to stay-ahead of the head movement. The M1 is a great chip, but it's not close on the GPU side. Not in the ballpark at all.
I've played Stereoscopically for well over a decade, and that's demanding enough, but at least you didn't need ultra-wide FOVs and 90fps. Moving to a Pimax 5K+ and even driving *that* HMD at resolutions high enough to be nice a crisp (an absolute minimum of 4K per eye, with everything beyond that being nice but not absolutely critical) requires immense GPU power (plus plenty of CPU power).
So this thing, when Apple releases it; it means that Apple's got something else up their sleeve that can power it properly. They've got to be really taking gaming performance and GPU performance and latency very, very seriously if they are going to drive a dual 8K HMD. That's good news for every Apple fan.
We also need to see what the FOV of this HMD is. A lot of the HMDs give you serious "tunnel vision." Many users don't mind that much, but then again a lot of us can't stand it (hence the drive towards wider FOV HMDs).