> It is possible to have excess productivity.
The most productive places in the world are also those with the highest incomes and wealth generation. "Excess productivity" is either temporary or a sector-specific phenomenon, it doesn't apply to society as a whole.
Temporary excess productivity can linger a very long time and sector-specific excess productivity can still be broadly damaging. Detroit and southeastern Michigan were devastated by the collapse of American automotive industry in the '00s, taking something like 10-15 years before starting to recover.
This is true; and in time it's entirely possible that AI makes us an overall wealthier and more productive society. However, from the article:
> “Most economists will acknowledge that technological progress can cause some adjustment problems in the short run. What is rarely noted is that the short run can be a lifetime.”
The redundant professionals will need to find other ways of generating wealth from their productivity, and that may not be possible in a reasonable amount of time. Not in the scope of their remaining lifetime.