I used to live in a university town with suburban density. The entire town was surrounded by cornfields. Half the population was just students. The city bus was extremely good, came every 5 minutes, went to all the major destinations like university, grocery, business parks, a wide variety of residential areas (even suburban neighborhoods of only family homes). Middle/high school kids would take the city bus alongside college students and adults, and there's no issue. In fact many immigrant student parents would be riding the bus with their kids, who got off at the middle/high school and then they'd stay on to get to the university. I didn't need to own even a used car and was able to have savings on grad student income. The sidewalks were wide, lined with grass, and well lit.
I thought, if even a rural university town could have such great infrastructure, surely dense major cities would have even better. So I moved to a major city later for work. I tried to take the bus then too. I walked 20 minutes to a bus stop and they came 20 minutes late, sidewalks just randomly stop at places, homeless guys everywhere. I never saw homeless people in that university town even with median income much lower than the city I live in now. What worked for buses in the university town was 1. safety, 2. frequency, 3. convenience, 4. pedestrian infrastructure, 5. public courtesy. The bus where I live now has none of that. They need to clean up the bus before anyone who has a choice will ride it. A major city can't even catch up to a university town decades ago?