The issue isn't that there isn't enough busywork that we can hand everyone to keep them busy if we really wanted to.The issue is that the value of that work is decreasing to next to nothing, because 1) the truly essential jobs are filled, stagnant, and increasingly automated, and 2) the non-essential jobs are as vulnerable to automation and AI as the essential jobs (there are burger-making robots now, and no, creative jobs aren't immune to this).
As a result, our resource distribution models mean that resources (money, if you like) are not going to be distributed in such a way that will guarantee people a means of living if they perform these non-essential jobs, because 1) the competition for those jobs is going to be ever-increasing, and 2) the value of them is going to drop because of human AND machine competition.
It's pretty simple to see, if you're willing to see it.Sure, there'll always be plenty of work for everyone willing to work for nothing or close to it, but we already have trouble as a society paying researchers or musicians as it is, and your "supportive" jobs are increasingly untenable as career paths outside of fairly specific geographic areas unless you're willing to live from paycheck to paycheck perpetually. Even some of your "essential" jobs are done on a largely volunteer basis in communities outside major cities (69% of firemen in the US are volunteers, not paid, for example).
Hence my initial conclusion:
...it's highly unlikely that there will ever be "enough" jobs again, so we need to consider what to do with people who just don't really cut it in terms of productivity and how we want to treat them as a society.