thousands of small companies sustain and employ humans, reliably now as sign makers? I live in a metropolitan area, sign makers were reliably found and nearby in my living memory. There are very few now, mainly as corporate franchises with catalog contents. How is the value of scarcity you refer to, being circulated in terms of reliable income and stability for humans living now? How plural are the products in modern markets

You're entirely right. I was talking about cultural value.

Things are really going to suck for working artists who can't adjust. That's not cool and I should have acknowledged it.

This assumes adjustment is even possible. Prior history suggests "adjust" is a euphemism for pivoting to unfulfilling lower wage work. If that seems like hyperbole to you I highly recommend taking some time out to research the before/after effects of globalization on rural factory towns in North America or the impact of high intensity corporate agriculture on family farms. If you want the tl;dr, just look up a graph of farmer suicides over time.

I mean, that has mostly been supplanted by graphic design as a field, which is still making signs, just not necessarily literally handmaking signs out of outdated technologies like neon tubes. And now also helping design websites and other such new technologies.