(This is all coming from someone who's probably going to jump back into PC/VR gaming for this experience, depending on the reveal and pre-release coverage...)
Given what other people in this thread have mentioned, you will not be moving within a virtual space via VR inputs with full body mapping to in-game movement, as that's a recipe for getting sick.
Given my experience with VR and playing games that required a fair amount of movement, Superhot VR and BeatSaber, the space needed was just enough to stand up, and move my arms around. I am really unsure of why this space requirement issue keeps popping up. Unless you're doing full room mapping, which I highly doubt this game will utilize, I cannot imagine that most people with an entertainment center or with a desk dedicated to their PC, don't have enough room to stand up and move their arms around...
Yes you can play some VR on a couch, but not Superhot, not Gorn, not Space Pirate Trainer. Very likely not Half Life Alyx.
I've used my VR setup from within cramped confines, but it's not something a non-enthusiast will do.
Edit: Also were forgetting a very important point mentioned above
"I'm not going to [...] lock my dogs outside just to play a video game."
At least for me, in all the spaces I have computers, if I stand up I have some stuff or shelves within arm's reach, because I want that stuff to be accessible - but that makes those spaces unusable for VR, because I'll hurt myself those things or myself if I'm swinging around without being able to see what's there.
At this point I prefer throwing $60 at 4-6 indie games and usually I'll find something with a couple of days or weeks playtime. Increasing the title's cost by an entire VR headset doesn't really improve my trust. Especially because a lot of the VR games I've seen on stream so far are just .. lackluster horror scare fares and entirely whacky things.
Born in 1992, HL1 was what really got me into gaming.
I worked on a game called Luna (https://store.steampowered.com/app/605770/Luna/) and many of the people who play tested it said it was the first VR game they played that didn't make them sick, previously they thought "VR makes me sick". It was optimized for player comfort and is a pretty slow paced relaxing game so I think that helped.
I don't get this move. But hey, maybe I'm wrong and this'll be what takes it mainstream... somehow.