Pontevedra has around 80K inhabitants, so it's practical to design it this way. But when cities are much bigger, problems start to arise. Not everyone can afford to live in the center (nor is there space for them, and building taller than a certain number of meters or floors is often forbidden for various reasons), so people begin moving farther out. Sure, there's public transport... but only until it takes six times…
if everyone is driving, noone is. This is simple game theory and a system fault happens when there are too many cars. You can't widen city streets.
For example: public transportation in NY is often faster and cheaper than a car + parking.