TFP is unlimited - Re: All this reminds me of something from Jerry Pornuelle
Nope - there's no limit to TFP, (that is, right up to the hard-limit ability where, Star Trek-like, we can abandon economics altogether as irrelevant.)
We already make cars in near-lights-out factories full of robots. You might say that there's an efficiency limit reached once we reduce the number of staff to zero. But there'll still be efficiency savings to be made on the amount of steel used in the cars, or in who's making the robots for the factories.
When I worked at Toyota, there was a kinda company meme going around that "We don't build cars - we build factories that make cars". Toyota 'got' the point that to be truly efficient, you go meta - you build something that builds something else efficiently, reproducibly, reliably.
A similar concept hypothetically applies to software engineering - you don't (generally) code at machine code 'bit' level - you abstract up to a higher level language that can churn out machine code.
Back in the physical world, we've got that abstraction still to come - but the singularity is fast approaching. Once robots can build robots (and once robots can design and build robots that build robots) then humans can take the day off and go to the beach.
How, in that future economy (of 99% permanent unemployment) we manage to give an income to those non-workers - via a Citizens Income to buy ice cream there - remains an exercise for the reader - and that's when politics will get really interesting.