> There is no obvious point where the microcomputer or the Internet made any major difference

I think it lags. There was a sag between the mid-70s and mid-90s, which is when computers and the Internet were being rapidly developed but weren't really hitting the business mainstream. But late 90s through today it clearly ramped up a lot -- my bet is this is because of IT. It just takes a long time, it's not a sharp jump because not every business gets on board immediately and productively.

My guess is AI ends up the same. But then again, I'm not an economist, only a developer, so I just think I can tell anything about that productivity graph.