Because it feels like prosperity. In a town with no public transportation and very few cars, getting a car would feel awesome. And it's just a lot easier for 1 well-off person to buy 1 car than for the entire town to get good public transit.
> it's just a lot easier for 1 well-off person to buy 1 car than for the entire town to get good public transit.
Sure, once the town is already built for cars. If it wasn't, having a car would be a pain with no parking and no space in the streets.
The question is why cities choose/chose to rebuild themselves for cars in the first place, and continuously in the third world as suggested by the OP and the book "Urbanism Imported or Exported: Native Aspirations and Foreign Plans" by Joe Nasr and Mercedes Volait.