SFO has no line for business class or high status travelers. (they have pre and clear).
That's the only difference.
Do other airports have? The only ones that I have been to (that have separate Customs and Security lines for Business Class travelers) are in India and Middle East. I have never seen a separate line anywhere in Canada or US.
That might be dependent on terminal.
Terminal 3 definitely has a United “Premier Access”/Star Alliance Gold line.
Not true; T3 has one, at least. I don't recall for the other terminals, but I'd be surprised if not. That sort of thing is mostly up the the airlines, though, no?
I never use it, though... the pre check line is usually as fast or faster.