They will do what countries do with surplus men: get them killed in a war. With India, which is under related pressure for resources, and Russia, which will be both ripe for picking and not going to give up without a fight. It seems inescapable to me. It is also a separate question from the extinction of homotude trickling down the global classes: it's not like those half billion men will turn gay for lack of women.

As far as philosophers go, it doesn't seem like current society feels a need for them anyway.