[Stretch]

I was assuming several players would coordinate the effort to make sure that the one player didn't run away with the game. Perhaps that's expecting too much from diplomacy, but I'm thinking of it as a game where people are actively opposing the strongest player. And presumably you wouldn't pool gems to give the nexus to the 2nd strongest player, just a player who the first guy couldn't destroy easily, perhaps with an agreement on how the profits should be doled out assuming it wasn't dispelled.

Kind of a pain to work out diplomatically, but better than having someone with a ridiculous gem income just destroy everyone.