Hardware moves fast. Once they crack fine motor skills in chaotic environments, even the plumbers could be buggered That saddle maker example is the exact trap economists keep falling into. They assume a magical new sector will always appear. When those newly invented roles are immediately swallowed by the next software update or hardware model, human labour hits a permanent dead end.
If money as we know it stops working, the reality is less like communism and more like corporate rationing. Communism implies the public owns the means of production. In reality, a tiny handful of tech giants will own the servers, the power grids, the food supply, and the robot fleets.
We will probably end up with a digital allowance—state credits handed out just to keep the peace and stop people rioting, which then get spent straight back into those same mega-corporations. The "own nothing" phalanx will get their wish for the majority.
In this world, the only real security left won't be a career or a degree. It will be owning tangible, physical assets before the ladder gets pulled up completely—paid-off property, a bit of land, and the practical skills to produce some of your own basics outside their system.