He is quite correct that societies can go backwards. There are many scenarios in which we would have 'the tech' and then end up abandoning and losing it. One simple example would be if one corporation profited more by wrecking 'the tech' of another and blocking its adoption, than the other could profit by furthering it. When it all comes down to money you get those suboptimal outcomes, and in the end somebody cashed in epically, but things were not made.
I'm pleased Elon gets this, but it's a chilling thought. We don't have to have MORE stuff, internets, communications etc. just because of Moore's Law, just because it's possible. We can also have progressively less because it's in someone's interest for it to be less.