Autonomous vehicles are supposed to increase road capacity by 250-300%, and make bus lanes actually viable, so no, not really.
And yes, I see Manhattan traffic every day.
Dude, this is a city of like 6 million and more come in from the suburbs every day for work. The subways are always packed to hell during rush hour and the bridges and tunnels are always a shitshow. Throwing the millions who use the subways on the roads is just going to destroy whatever capacity would be created by these cars.
The subway ain't going nowhere. Autonomous cars and shit might make the roads a bit less congested, but there's no way it gets rid of the need for the subway.