If I had to guess, part of it is sprawl. Chicago packs a lot more people in 7197 square miles than either Houston or Dallas do in 8827 and 8928 square miles respectively.

Another piece is likely original city design and the way the city itself grew up. I’d have to do some digging to prove that one way or another.

One last piece (well, two tied together) is political will and political capital. Houston is a LOT of oil money so you can spend your time trying to make sure people have access to city services or you can fight against the people who make money on keeping more cars on the road. Even the blue folks are employed by O&G, adjacent services (manufacturing), or service industries that are fed by the folks in O&G (food). It’s an uphill battle. Dallas is more tech dependent so they had an easier time with DART but missing a bus transfer can still be over an hour ordeal.