I commuted by tube in London for 3 years, my most recent house was 1 minute walk from the station and my office was also 1 min walk from a very busy central station. So basically door to door. Even still, commuting was
not a pleasant experience.
The human congestion in the central tube stations at rush hour is appalling, as is the air quality down there, as is the lack of personal space on the train itself. It's a very stressful, undignified experience for everyone.
I'd much rather be spending a bit of extra time in traffic, sat comfortably in a self-driving taxi, than take the tube. That said, I think there's good reason to believe that as self-driving cars become more prevalent, traffic flows will actually improve due to better flow management, less need for traffic lights, and fewer cars parked.
Rail does the job, but it does not do it elegantly. It's very unpleasant to take mass transit railways in major world cities. Nobody who's done it for any length of time would reasonably contest this. Self-driving personal vehicles could be a major improvement on the commuting experience, if indeed the future involves commuting at all - a vast increase in remote work may simply sidestep the issue completely by the time self-driving cars are a mature tech.