Ken Avidor has written an obituary for Personal Rapid Transit, at least in Minnesota: End of an era for Personal Rapid Transit | Twin Cities Daily Planet.
The technology was always more of a gadget than something that serves much in the way of practical transportation. In The Transportation Experience we called it a technology in search of a market.
Assuming it works technically, does it work economically. I.e. under what conditions does it move people more cost effectively than they can move now. Establishing this niche is essential for any technology. Clearly the market does not yet believe such a niche exists.
There are always complaints about subsidy for the competition. But that is weak, if the economics for PRT were really strong, that subsidy would not matter.
There are network effects with any transportation technology. The problem is one of chicken and egg, no one will build a large enough network for the system to serve enough people to justify itself. Most transportation systems evolve by adapting new vehicles to existing "roads", few try to deploy both simultaneously. The elevator and railroad (in 1825) being notable exceptions.
Combining the best features of roads and rails is a noble effort. I suspect success however will come from independent smart cars that can drive themselves on existing roads (which go almost everywhere) in traffic with human controlled vehicles.
PRT suffers the same flaws as the original IVHS system that was cancelled back in 1997, it has no practical deployment path.