“If this is true, then at the margin, two 10% pledgers have a lower chance of both defaulting and thus have a higher expected value.”
I don’t think this is true, at least not taken naively. Ie, 70%20%=70%10%*2. Decreasing variance isn’t quite the same thing as expected value, and there are so many problems in the world that needs money that decreasing variance just isn’t that important relatively to channeling as much (expected) income as possible to the most effective causes.
“If this is true, then at the margin, two 10% pledgers have a lower chance of both defaulting and thus have a higher expected value.”
I don’t think this is true, at least not taken naively. Ie, 70%20%=70%10%*2. Decreasing variance isn’t quite the same thing as expected value, and there are so many problems in the world that needs money that decreasing variance just isn’t that important relatively to channeling as much (expected) income as possible to the most effective causes.