When you argue for housing reform to legalize denser development in our cities, you quickly learn that some people hate density. Like, really hate density, with visceral disgust and contempt for any development pattern that involves buildings being tall or close together.
Walking 12 miles would be a lot less tiring once you are used to it. I remember it took me 2 weeks to feel normal again when I started biking to work. Plus walking more throughout our days is going to keep us healthier.