It *sounds* like they are not planning to tether, which seems kind of crazy since even the apple watch was, in a sense, “tethered” for most of its life. But who knows. There have been so many confusing rumors - a developer-focussed early version that looks like traditional VR goggles with glasses following in a couple years, tethered VR goggles and untethered glasses, etc. etc.
Maybe their dev kit will be more of a traditional headset but if that's what they're working on for consumer, its not going to get off the ground, because its just doing the same thing everyone else is doing - which is still a niche market despite being "just around the corner" for the past 30 years (Yeah, i remember the first previews/steps for VR back in the 90s).
I feel the real problem with AR/VR gear at the moment is that everyone is basically trying to stick a CPU+GPU+RAM+Battery
on your head and its just a recipe for something that's heavy, unwieldy and uncomfortable for anything more than short bursts of use.
I've used Hololens 1, Hololens 2 and own a Quest 2 - and whilst its cool what these devices can do, i really feel that the focus should be on something that's more lightweight by stripping everything but the bare minimum off to an accompanying device that is close by but not on your head (e.g., pocket, backpack, whatever) where the bulk of the processing can happen; for reasons of bulk/heat/weight/battery life, etc.
The Quest 2 can do this today with wireless tethering to a PC - but it is still also a standalone unit and still has all the associated components inside it.
The tech to do some lightweight glasses is there, and Apple have the most cutting edge, best performing gear in this space to do it with...