People valuing something is not at all the same as people spending money for it. For one, there is always competition with an abundance of freely available material. At the very least, you’d have to compare with a situation where nothing of the sort whatsoever would be freely available, and that’s very hard to do.

That being said, I’m skeptical of UBI being workable as well.

I think that's an unbelievably cynical worldview, one I don't agree with at all, but within that view: what of the things people value, but which they do not pay for? Much of the tech of the world is built on the free labour of FOSS developers. Are they not contributing to society because they are not compensated for their contributions?

It's quite possible to be creative while not contributing to society or whatnot.

A crappy sand castle from a eight-year old that will be torn down when the tide comes in is not really contributing to anything useful, but can be quite creative.

Counterexample:Ignaz Semmelweis, who discovered in the 1840s that hand-washing dramatically reduced deaths in childbirth. The medical establishment rejected his findings, and he was institutionalized and died tragically, vindicated only after his death.

Surely this was a contribution even if not valued at the point of making it.

Even given the other objections to your argument, there are an extraordinary number of examples of now-very-appreciated artists, writers, etc whose work was not valued at the time they were creating it.