That's fair! I'm kind of exploring here, it's not like I'm firmly set on any of these measurements. (And for what it's worth, I think jwz's statement is wrong about time travel too, although it's right somewhat more often.)

The thing that got me was Wrede's statement that she was going to depopulate the hemisphere but that it wouldn't be a "wildly divergent" alternate history. Perhaps what I'm getting at is just that large things need to... appropriately deform the story they're in? Well, maybe I'll word it better next time.