Tethering to a mac or iPhone might not be the worst idea, as the headset becomes less of a headset and more of a mobile monitor or workstation. That certainly not worth $3500, but it could be worth $1k to a lot of people. Kill a lot of the sensors and finger gestures (or scale them back) and switch to a more mouse and keyboard interface and I think it might actually do well. Oddly, it's probably an easier sell as an accessory like the watch than a standalone product like an iPhone.
I don't think the Pro line is viable beyond a very wealthy and niche market. If they're pushing it back by a year or more, it might be effectively dead even if they're not admitting it. It's just way too much for what is always going to be a novelty.
Trying to focus the purpose of the Vision Pro on FaceTime and video watching is... probably not going to work. It's too ****ing expensive. Even a $1500 slimmed down version is too expensive. I can buy a really nice, really big TV for watching videos and movies and share it with the whole family for that price. No one really needs (or probably wants) a headset for an uncanny valley FaceTime session. The strategy that Apple used to make a market for the watch won't work for the Vision Pro or any Vision for that matter because it's not a (relatively) cheap, unobtrusive accessory that gives constant access and convenience. It's the exact opposite, and the justification for it is going to need to be something beyond simple leisure activities. The watch filled a small niche that nothing else did, and it did it cheap enough to be worth it to a lot of users. A headset that's as expensive as a phone or computer that's trying to be a personal TV just isn't the same.