This is a very pessimistic take on our capabilities.
Retrofitting modern (past century technology) transport systems onto cities that are a ~ 1,000 years old is things that many cities have managed to do. Almost any capital city in Europe would make a good example.
Can you elucidate on why doing it in Houston is 'virtually impossible'?
> It's a 100 x 100 mile area. I grew up there and drove 5 miles to high school, through sprawling neighborhoods.
TFA suggest that a million cars within the Houston Metropolitan Area were destroyed. According to wikipedia this is ~ 4,300 sq km.
You've suggested that Houston is 100x100miles ... which is about 25,000 sq km.
You can't both be right.
For reference, Sydney metro area is estimated at around 12,000 sq km - three times the size of Houston. Australia's renowned for low population density (equating to relatively high cost of public transport infrastructure per person) ... and yet.