Sure, it's just ...pretty odd? for OP to say "backpacks were marginalized as being associated with being too poor to own a car" when it's 65% of people who do not use a car in this context at all.

(aside: transit is up to 25% again recently, apparently; https://www.sfchronicle.com/bayarea/article/remote-work-home.... And that graph has an even more interesting number which is that in 2019 transit was the plurality.)

This was 20-25 years ago. No Uber Cab, no Google shuttles, no e-bikes, no rental scooters, Caltrain was diesel and hadn't been renovated, and there was no real-time tracking of Muni buses' positions, so unless you were taking an express bus, you had no idea when the bus would arrive at the stop. And a large part of San Francisco's population was still poor.

There were a lot of people who didn't use a car in that context at all, but people who could mostly did.