Unless you go for UBI, art subsidies will be finite. You need a measure to decide who gets subsidized and who doesn't. We're not talking about people doing art as a hobby after all, but about the government paying people to make art.

I'm not saying artists should optimize for money but financial sustainability. It seems like a good target because it indicates popularity and means you need less subsidies. You don't need to make _all_ the money or even break even, but if nobody is interested in paying you, the odds are good that you're not enriching many peoples lives.