<i>&gt; Barring space travel, it&#x27;s hard to even imagine 1000x growth over the next 700 years in any real sense</i><p>Why not? 700 years ago most of the things that people produce today weren&#x27;t even conceivable, and any sort of comparison of functionality is going to end up involving large factors of improvement. For example, how much more functional is a smartphone with the ability to dial anywhere in the world and connect to the Internet, compared to writing a letter that would travel by horseback or sailing ship, which was the best known communication technology 700 years ago? I have no problem at all saying that the smartphone is at least 1000 times more functional, which means that productivity needs to have gone up by a similarly large factor for smartphones now to be about as ubiquitous as letters were then.