I agree with you on all these points, even if I haven't experienced them myself in SF. I used to take the T and used the bus system in the greater Boston area for a couple of years and had similar experiences. Quite a few people drank beer out of gatorade bottles for breakfast, etc. One guy nearly threw up in my lap.

The point I'm trying to make is that public transit can be made much better and more enjoyable. Instead of saying "well, it sucks now" we should say "it sucks now, let's make it better". The budgets currently devoted to maintaining roads, traffic police, etc. could be used to improve public transit instead. Motorized walkways could double or triple your walking speed (something you say you already do) in lots of places.

I grew up in Kharkiv, Ukraine, a city with roughly 1m people and several public transit options: subway, tram/light rail, commuter rail, taxis, and buses. While some of these got to be somewhat gross, the subway specifically was always great: always clean, always air conditioned, marble floors and walls. By contrast, Boston's T/subway/metro is always looking like there is either construction or rodent extermination going on, and it is incredibly hot at all times. It's also incredibly noisy because of the wrong size chassis on some of the train. I believe that if a country like Ukraine can have nice public transit, the US should be able to figure it out too.