Why is the IQ 70 kid not able to do laundry as so many others once did earlier, if the economy is so productive - shouldn't someone be able to hire him in his area of Ricardian comparative advantage?

The left tail on the distribution for inventive, creative, bright people seems highly likely to be fatter than the right tail. You need to be genetically gifted enough and have had the right encouragement, and lived in the right intellectual environment, to go on to create neat inventions and research and so on - that automation supposedly frees people up for/ If it is, then rather than freeing people up for better jobs, it frees people up to compete for a finite number of worse jobs.

Or, in other words, it seems to me like there's a non-trivial possibility that the people who were doing admin tasks are being displaced into doing laundry tasks instead. That what would have been being done by the 70 IQ kid is now being done by a 100 IQ adult.