Several orders of magnitude more children would be saved from mosquito nets than community theater, and each of them has a chance to find a cure to cancer. Then there's a couple orders of magnitude of children who wouldn't die, but whose lives would have otherwise been significantly disrupted by malaria, hookworm or vitamin A deficiency. All these children could go on to find cures to cancer or at the very least live more meaningful lives.

Obviously, this isn't to say we should donate any less to community theaters, though I think that's a different type of donation. That is partially altruistic, but on some level it fulfills the same satisfaction as a purchase.