People do giant shopping trips exactly because the whole process is so cumbersome.
The US has the longest commutes of any country in the world because of urban sprawl and zoning. Car-free cities offer an alternative to that way of life.
Just a data point. I'd love to hear how often urbanites go to the grocery store and how long each trip typically takes.
Urbanites still have the option to go to a big-box grocery store. Mine is an 8-minute drive away, but we just never go there.
My personal feeling is being able to stock up in bulk is a net timesaving benefit of car-centric living, BUT the tradeoff comes when you only need a few things from the store. On the one hand, it's only about once or twice a month that I need to go to the store because I need just 2-3 very specific things. However it's a major annoyance, and it'd definitely be nice to be able to walk a short distance to get them.
I lived in Mumbai starting 7:30 in morning I reach office by 10AM after changing buses and trains. Leave office at 6:30 -7 in evening and hit home by ~10 pm. And even those days I worked in IT so not exactly among poor who have to live far away.
Claiming US commute being longest is just ignoring how billions outside North America/Europe lives.