Anecdotally I started getting more on board with this movement from the increased information on urban planning from Youtube channels like Not Just Bikes & City Beautiful. I personally never conceived of walkability, having lived in car-centric suburbia my entire life. I now live in a walkable area and can confirm that, for me, my quality of life has improved.
I had an epiphany at some point when I realized my elementary school was easily within walking distance (~1 mile away) but the thought of walking or biking to school absolutely _never_ crossed my mind because I was in a subdivision and a four-lane split highway with a 55 MPH speed limit separated my house and the school.
I got into running after college and lived in a borough where things were walkable and some decent landmarks were no more than two miles away. Things felt close, and accessible. I went home for Thanksgiving once and realized that, while there were plenty of things that were kind of in range (grocery store ~2.5mi, shopping mall ~3mi, mini-golf ~1.5mi), the fact that it all ran through that highway made everything feel far, and it was never feasible to do anything but drive.
And I'm not even sure the solve needs "make my hometown area dense"! But if you had protected bike lanes on the highway and made everyone slow down a bit to let pedestrians through, that could be a massive improvement for everyone.
Now that people are working from home, it might not be necessary for suburban families to have two cars. I would know, I've been one-car for over four years now I think. Additions like walking paths and bike lanes and better bus access can make a huge difference and can save thousands of dollars a year on vehicle costs.
