This has been on my mind a lot recently as my friend was arguing basically the same thing that you're laying out here.
I think that it is a bit too pessimistic.
An economy is just the transfer of goods and services right, but just measured through a currency.
Even in an AI world, people will still need goods and services, but they might just be different things (and lots of the same).
Short term redundancies for sure, but a new opportunities and systems in the long run
That's how I see it anyway.
Nice article.