Earlier quoted context omitted.
> one might wonder why they apparently are not able to sell their art for the same amount of money "Public goods" like parks, museums, bridges, roadways, transit, nature preserves, community spaces, and public safety services produce both direct value to their immediate users as well as substantial diffuse value to their community. Direct value can be captured by user fees, tolls, subscriptions, etc but capturing dif…
Your argument makes sense, but a park has a measurable scope. We all want it to be X sqft, with Y trees, and it will cost Z dollars. Are you going to force artists to make the specific art that the community is in need of, or can they just do nothing?
Expect something? Yes. Enforce it? Not sure for the first tranche, but make it a prerequisite for continued funding.
One big obstacle is, of course, how to define what to expect from each artist. For example, you can't expect the same level of output from sculptors and musicians. Another big obstacle is obviously the expected quality of output.
I don't pretend to know the solutions to either of those obstacles, but they should be surmountable [1]. I think it's fair to expect some output in exchange for funding, but it doesn't have to be a high expectation.
Personally, I like the idea of hiring artists as full-time with particular projects in mind [2], but intentionally leaving ~50% of their time to personal projects.
[1] Perhaps artist communities themselves could discuss ways to make this exchange work for all parties.
[2] Murals, restorations, beautification of public spaces, etc.