Anything that's giving you a per-person riding experience is not going to perform as well as batching a bunch of people together for a common ride.
Distributed systems that have to coordinate multiple moving parts are more prone to breakage, and single points of failure.
Not to mention the infrastructure that's required to build millions of what it sounds like are indivdiual train cars (albeit, much smaller), and the tracks required to get people to where they're going.
You're reinventing the train, but worse there... (https://www.youtube.com/watch?v=fvvA_GToc0M&ab_channel=AdamS...)
Better would be to make train cars with seats that have better isolation for people traveling in small groups. But honestly, I think we're overestimating the number of people that need this. And there's a small possibly they could still be serviced by a small car in a world where 80% of people are able to use other services.
This would probably make some people uncomfortable, but one fantasy I can imagine which might be nice is to have private transport capsules. We could own our own capsule and decorate/style it to our liking. It has common exterior form factor, with power, plumbing, etc. connectors.
We go from home to the nearest capsule station (where ours is in automated storage). We schedule picking of the capsule so it is ready for us upon our arrival. We set the destination, hop in, and the delivery system takes us for a ride. Hell, with a nice private capsule you could sleep, watch movies, work, even have "fun" with a partner. The system (ideally) ensures you arrive at your desired capsule station end point, whereby you exit and set your storage option.
This would take more space than current public transport (a lot more!), but it would take less space than a typical individual car, not to mention less roads as the exchange systems would be optimized and operating in three dimensions.