I honestly don't see how that will be possible, is Apple going to develop games for the App Store competing against HL Alyx, are they going to tether it to a Mac with Pro AMD GPUs or establish a gaming cloud services with ultra low latency? Even if they got the headset right you would still need to plumb it into a PC to challenge the best and have the software to back it up.
I think far more likely is an AR solution closer to Google Glass or something where you can consume media TV shows etc... They will imho do their own thing and then rollout the marketing machine to present it as the best thing eva.
Did you not read my post? I said "
IF they are serious about
VR" If as you say, their focus is AR, that means they might not even produce a VR headset or any VR headset they release will be an after thought.
If, on the other hand, VR is their priority, then Apple will do what Apple do best. Make a very compelling product that's easy to use. I don't know why you think this would be so impossible? It would be pretty simple to use as a VR headset that connects to a PC or MAC, just a decoder and a display. As a standalone headset it would only use the Apple Store. There would be no shortage of Developers, and it wouldn't be too onerous a task for developers of games like Beat Saber etc. to port their games across to the Apple Store.