If this were 10 years ago, I would say there is the potential for autonomy, but now that Beidou-III and 5G are here, real-time decimeter level geolocation is possible. When you combine this with the improving AI coming in the next few years, I think the autonomy issue will be solved, not just for mass transit but also for every day vehicles. There is that middle ground concerning scale you're talking about but I just don't think it's worth the hassle for what I believe are relatively small gains.
It really depends on the city, its typical roads, specific transport preferences and idiosyncrasies. Even topography. I still think it has a place if there is an interest to connect major nodes within a concentrically arranged density city. Buses provide service to more remote destinations since they deal with terrain much better than something like this but the strength here really is the scaling and the ease and pace of which this option can be adopted. No need to seal off major roads for years to create tracks. All vehicles continue operating as before. Rather than being close to impossible, changes to routes can be done within hours. Also already autonomous ready without requiring additional tech. This is just simpler and more fool proof in comparison.
Trains are entirely different class of transport. Not in this discussion. Monorails are horrible because subways are simply superior and the investment required isn't
that much more for a typical city with mostly silt and clay underground. This transport vehicle offers far more than buses. Buses are supposed to service more out of reach destinations and while they're not as polluting now, their energy efficiency probably won't be able to match this method. Once occupation rates and patterns are accounted for, these options should be even more superior. That's not saying they'll be adopted everywhere because existing methods are efficient and effective enough to warrant not changing anything.
Basically I'm trying to say that transport engineers around the world have figured that trams are quite a good solution and an addition to complement intercity subways and buses (if the city and traffic behaviour fits the technology). This is just a tram that can be applied without years of laying tracks and can be changed however, whenever. It just lacks the greater energy efficiency of an equivalent tram.
Privately owned cars are going to become phased out. They'll probably be ride sharing autonomous vehicles for that option but it's on its way out while it leaves massive infrastructure - roads. Tram tracks can't be applied easily on all roads.