I live in London, and my "commute" involves walking next door, to my office. When I worked in central London I commuted by tube or train.
However, when I travel out of London, I often have to lug stuff about - stuff that I couldn't physically carry onto tubes, then a train, then walk a mile with at the other end, so I couldn't give up driving.
And there is the time issue - public transport works pretty well within a big city if you are travelling the popular mainly radial routes, not so well if you have three or four places to visit that are each a few miles apart. I once worked out that by driving around suburban London I could visit four places I needed to go to in an hour and a half, but by waiting for tubes, buses or trains it would have taken pretty much all day.
Also, as petrol goes up in price, fewer people will be driving, which actually makes driving more efficient (less congestion so faster journey times) for those who continue to drive.
Giles..