It's a tragedy of the commons. For an individual, private car is faster, but the resulting traffic ultimately makes things slower for everyone. Public transit in Tokyo is faster than private cars in car-oriented cities.
That’s not true. Public transit in Tokyo is slower than driving in Dallas or LA. Average one-way commute in LA is just over 30 minutes: https://fred.stlouisfed.org/series/B080ACS006037. For Tokyo it’s 45-60 minutes based on sources I’ve seen online.
As I said on https://news.ycombinator.com/item?id=46214609 , that statistic doesn't mean what you think it does. The article I linked doesn't have figures for Tokyo but it has Shanghai which is comparable; there are around 4x as many jobs within 30 minutes by transit in Shanghai as by car in LA, while the population is only 1.5x bigger.