No, they can still build robots inefficiently at low wages. And thanks to the heavy automation their real wage would be decent.
> older person is going to suddenly go back to school to learn a new trade is simply not how people in general work.
What if they have good incentives to go back to school?
I don't need to, I'm not making it.
> What if they have good incentives to go back to school?
No amount of schooling will make the half of the population with an IQ below 100 able to hold a high tech knowledge job. You are ignoring the realities of the human condition. All of mankind simply cannot and won't ever be able to do knowledge work. When you kill the low skill labor jobs with automation, you kill the only jobs some people will ever be able to do.
We're discussing the fact that change is happening faster than people can adapt; that long term jobs won't run out has no bearing on the issue being discussed, that the rate of automation is happening faster than people can adjust hurting low wage workers. Beyond that, when intelligent machine are invented, that fallacy will be outdated, the past is not always prologue. Intelligent machines are unprecedented in human history, this will invalidate many old fallacies. Jobs for low skilled people will run out, it's inevitable.