I think there are valid points on both sides. Overhead lines in dense city streets are ugly be they monorail, PRT, or elevated rail. Capacity (at rush hour, at train stations and stadiums) is an issue. It is yet to be proven. But those who say something is impossible because it hasn't been done yet are too extreme the other way.

The dual mode concept (which is indeed similar to the concept I outline, though it predates the idea of electric cars and the ability to charge and control them on the line) has a number of advantages in terms of adoption. In particular getting the people to pay for the cars, and having the system only build the infrastructure is less of a leap from today's system.

Classic PRT would have no problem getting adopted in a city where most people are used to not driving (taxi/transit) but may not fit as well for environments where people insist on driving.

Though I generally think, based on the speed at which transit systems develop new ideas, that it's more likely we'll see crash-avoiding self-driving cars on the regular roads, because we already have the regular roads and they aren't going away any time soon.

We could actually have self-driving vehicles on specially prepared roads (guide wires and signals etc.) but we can't deal with what happens if a pedestrian or ordinary car gets in the way.

I was trying to imagine what you could do with one-way guideway down the center of existing roads with a concrete barrier around it (costing a lane, which is recovered from street parking spots no longer needed.) But you can't have barrier in the intersections. To make this work you would need long red lights for the cars -- and deliberate long gaps in the PRT slots for when the cars get green lights. For "stations" passengers would have to take the controls of the vehicle in special exits from the track and manually take it to the station (small parking area), and then manually bring it to a track entry point.

But the cars could still hit a pedestrian or other car in intersections, and it would mean nobody could left-turn out of driveways along the streets.