Leaving aside Aumann questions: If people like that think that the Future of Humanity Institute, work on human rationality, or Giving What We Can has a large probability of catalyzing the creation of an effective institution, they should quite plausibly be looking there instead. "I should be doing something I think is at least medium-probably remedying the sheerly stupid situation humanity has gotten itself into with respect to the intelligence explosion" seems like a valuable summary heuristic.

If you can't think of anything medium-probable, using that as an excuse to do nothing is unacceptable. Figure out which of the people trying to address the problem seem most competent and gamble on something interesting happening if you give them more money. Money is the unit of caring and I can't begin to tell you how much things change when you add more money to them. Imagine what the global financial sector would look like if it was funded to the tune of $600,000/year. You would probably think it wasn't worth scaling up Earth's financial sector.