I mostly agree with this.

I think that the idea of desires converging if “we knew more, thought faster, were more the people we wished we were, and had grown up closer together” relies on assumptions of relatively little self-modification. Once we get uploads and the capability for drastic self-modification, all kinds of people and subcultures will want to use it. Given the chance and enough time, we might out-speciate the beetle (to borrow Anders Sandberg's phrase), filling pretty much every corner of posthuman mindspace. There'll be minds so strange that we won't even recognize them as humans, and we'll hardly have convergent preferences with them.

Of course, that's assuming that no AI or mind with a first-mover advantage simply takes over and outcompetes everyone else. Evolutionary pressures might prune the initial diversity a lot, too - if you're so alien that you can't even communicate with ordinary humans, you may have difficulties paying the rent for your server farm.