Quoted By:
If you had the same amount of people for say a bus waiting for their own personal taxi, even in a grade-separated "rapid transit" tunnel, you would still have longer wait times due to a) the amount of traffic generated by space in the tunnel and b) the low throughput meaning each rider will be left waiting for their personal assigned taxi to arrive out of the one tunnel and park for them at the station.
This is exactly what happens at the Vegas loop, and it's basically as quick if not quicker to walk between one station to another.
There is absolutely no reason why taxi rapid transit should ever be considered an efficient form of public transportation