The ‘under 1 billion’ part implies genocide, because that is literally never gonna happen - in a time frame where we wouldn’t have to rethink housing and nature right now and the next few decades - otherwise without a major worldwide catastrophe. Sure, climate change might take care of it (again, decades away and people need housing now, also, these solutions actually help with climate change) but then we won’t have to worry about silly things like housing ever again.