Traffic and housing in Seattle are problems only the government can solve, as they're the ones that created the laws and incentives that cause the problems. No use dumping money into a pit.
I actually see the value of lobbying, and think that would be an excellent idea. But lobbying has such a nasty connotation, I doubt it would pad the ego of a philanthropist (call me a cynic, but I'd wager 90% of philanthropy is just a way for people to garner attention and praise).
I don't think lobbying would be nearly as bad if a) we had publicly funded elections, which takes away the incentive for politicians to be beholden to the interests of donors, and b) we had a mechanism (possibly through a branch of judicial review?) to repeal or amend laws that don't achieve their stated goals.