I don't mean materially private, I know we're fishbowls on wheels, but culturally private, as in people often refer to it as such.
It's one of the only times most people are disconnected from internet/work-tech because there is substantial risk of life and limb if they engaged (I know people have made this work regardless, I'm talking about cultures, not outliers)
Also this human need for privacy, if that's the reason to commute, is coming at the cost of literally destroying the planet.
There has to be a healthier way to satisfy these baseline psychological needs. Climate collapsing death machines may be how humans have transported themselves for a while but it shouldn't be the main go-to for how they are alone with their thoughts
I'm being a bit facetious, but ultimately, this lack of privacy is all self-inflicted.
Someday we'll be saying that travel is only for the rich - everyone else will be forced to use VR, and they will be brainwashed to like it. As they say, American lifestyles are only sustainable for the 1%. The rest of us should eat bugs and live in pods.
As we move into cities, production becomes cheaper - which means we produce more, which means we can support more people, which means we need to increase efficiency even more.
I'm not sure that this is preferable to life without technology. Aren't family and small moments the things that make life worth living? Squeezing out a few more years of expected lifespan hardly seems worth the tradeoff to me.
Personally, I don't think this is sustainable.