[Begin Rant]
This brings up the biggest problem I have with Bay Area public trasnportation. I live 11 miles from work, but it's impossible to get there via any reasonable public transportation-based route in less than 1 hour. On flat land, I can bike at least 50% faster than that, in normal clothes, without breaking a sweat.
The BART portion of my trip takes around 25 minutes. Once I get off BART, my choices are basically to take Muni or walk. Walking gets me there reliably in around 25-30 minutes. Muni theoretically gets me there in around 15 minutes, but that's in an ideal world where there are no delays on the line and I don't have to wait to transfer. I'd rather end the day $2.25 richer and get the little bit of exercise than save a whole 15 minutes. And, of course, the same goes for the trip home.
People who live in, say, the Outer Sunset and commute to SOMA or the Financial District have even worse options. Your Muni trip involves taking 2 or 3 buses, and there's no other reasonable way to make the commute than drive (and we know how miserable and expensive driving in SF is).
[End Rant]