[friend_and_foe]

But that's not what we are talking about here. We are talking largely about innovation, the productivity boom was the period people went from horses to cars. Selling shiny new things to replace the same things with a patina and calling it productivity is like breaking windows to fix them and calling that productivity. So you expect to see a plateau in truly productive car manufacture for example (that manufacturers hope to squeeze revenue beyond with unproductive manufacture, such as planned obsolescence, things that can't be sold on the secondary market, etc) but you don't expect to see an overall plateau of productivity unless 1) innovation is stifled or 2) everything that people could possibly need or want has been invented. I don't think the latter is true.