The answer doesn't have to be that everyone has a job. It could be universal basic income. It could be any array of things.
But the question is, does Patreon, OSS grants and the like scale to the entire population of a country? My instinct is "no". Yet it's likely that a lot of people will be looking for alternative means by which to live life within our lifetimes, and no-one is really looking for broadly applicable answers.
There's only one (more or less) answer - you can't have a few people owning the output of the machines. The wealth will have to be spread out - whether that's thru some form of Socialism/Communism that doesn't exist yet or not, I don't know.
But once you get to more or less full automation, the only people who would make money under the current system would be the owners - there wouldn't need to be any workers.
I would highly recommend reading Debt the First 5000 Years. It goes into the history of debt, money and slavery (which are all very closely related to war).
I think things will change dramatically if we can solve energy scarcity. Much of our wealth in society is based around the availability of resources. What people forget about with 3D printers is they still need oil; and you can't (easily) print circuit boards. Humanity needs something on the level as replicator technology from Star Trek.
I want to believe, but I don't think that type of alchemy is feasible; at least not until we solve the energy problem. A breakthrough in LENR or tokamak fusion reactors could change the world dramatically.
But the question is, does Patreon, OSS grants and the like scale to the entire population of a country? My instinct is "no". Yet it's likely that a lot of people will be looking for alternative means by which to live life within our lifetimes, and no-one is really looking for broadly applicable answers.