I sometimes ask people to consider a thought experiment about planning for 50 to 100 billion people, after stepping them through the idea that while the expansion rate is starting to slow, it really isn't something we should rely on. I find most people just shut down, several stating that it isn't something we should ever think about. I find it strangely poetic that many people are perfectly willing to think about billions of people dying, but not about billions of people being born.