SIAI would probably be at least in competition for best charity in the world even if their chance for direct success was zero and their only actual success raising awareness of the problem.

I did a wildly guessing back of the envelope type calculation on that a while ago and even with very conservative estimations of the chance of a negative singularity and completely discounting any effect on the far future as well as any possibility of a positive singularity SIAI scored about 1 saved life per $1000.