I think there's good reason to be optimistic about diversity at that scale. The environment shapes the direction your easiest path takes. Available material as

I think there's good reason to be optimistic about diversity at that scale. The environment shapes the direction your easiest path takes. Available material as well as the policies of an alien culture may be enough to send the local minima for optimizations way sideways. Who can say how it plays out on a multi-planet civilization scale, but I think we'd have enough reasons to be happy if we got there :)