Maintaining isn't what people are aiming for though, they want improvement. People are not satisfied by objectively living much better lives than some king or pope 500 years ago.
Second, who said anything about the rate of change going to zero? Even if productivity suddenly dropped to 1948 levels, it’s not like we’d be living in 1948. It’s not a time machine.
I agree. What follows from that? Do we let some people live in the 21st century but hide their life style from the rest so we can keep them happy at a level that we can more easily automate?
And sure, it's not going to reverse necessarily (though it will to some degree, because we can't "automate" the 2020 economy). My point is that people aren't satisfied with no progress. Wanting to change things for the better seems to be a very natural part of humanity, making plans that don't account for that drive doesn't seem wise.
Workers are more productive now than they ever have been.[0] Productivity was up 253% since 1948 seven years ago. For decades they’ve been promising us the 20 hour work week, and it’s here. In fact it’s only 15 hours comparatively.
The point is: you don’t need everyone to work full time everyday for a society to maintain a healthy standard of living.
[0] https://money.cnn.com/2013/03/07/news/economy/compensation-p...