The question is, if you believe AI will eventually catch up with all jobs that exist today, what skill could a significant portion of the population possibly have at that point, that the AIs would not also match?
Perhaps we'll have social constructs to provide jobs, similar to how people are willing to overpay for designer goods instead of copies (e.g. maybe 'hand-crafted' will take on a whole new meaning). But from a solely economic perspective, it seems like a matter of when, not if, an AI could more efficiently do most jobs.