I think you underestimate what a difference riding in back makes.
Yes, yes, when you drive, you get angry and aggressive. I do too; my observation from taking ride share (I gave away my car and now almost exclusively use the rideshare) is that almost everyone rages out from time to time when they drive.
Sitting in back with a book is such a different experience. "Wow, I used to be like that?" I mean, it seems so weird to see someone get mad about traffic when you haven't taken the wheel for a month yourself.
Edit:
To be sure, if we don't get full level-4; if you still need to be the 'safety driver' and actually pay attention, that's a different thing, and yeah, that's a whole lot less useful.
And to be clear, I am not saying that I think we are close to full level-4. I'm just saying that if we get there? it will be wonderful in ways that weren't obvious to me until I switched from driving to being driven for quite some time.