I would like to see what data you assumption that public transit is slower than car is based on but I'm quite sure it's not true. From my experience, car as always been slower than walking + public transport. And much more painful and stressful. Those numbers might also mean that having a good public transport infrastructure allows people to work from further away than car does.

Comparing salaries is also quite a broken. You can turn what you says around. Maybe Paris has a great transport system because of better investment in public infrastructure and distribution of wealth. I have no idea if what you say about Houston is true, but if it's the case, maybe the lack of public infrastructure is due to the lack of investment in public transportation, causing the obligation to have car, which is expensive for the most vulnerable households and causing all the environmental issues we all know.