Seriously: Who comes up with that? We finance culture because it needs to avoid the markets not to become a dull product. At best they will aim at some mainstream, not at all supporting any advances in art.
It's unreasonable to ask people to put their hands in their pockets and give you their hard-earned money if you can't explain exactly what you're going to do with it. That way lies Tracy Emin putting her unmade bed on display, or whatshisname and his pickled sheep - laughing all the way to the bank.
Most funding however is not profit oriented. Often it is paying the material, offering a residency (not payed rent anywhere you want) or small financial aid because it's still very hard to make a living as an artist (unless you play/serve the art-market well).
Most any of these grants have a jury, the better ones actually have a small jury and more often than not the influence of a single jury is even enhanced by having some kind of weak positive veto. If a single member of the jury thinks someone is really worth it, than it is made highly likely that he gets funded. This is because democracy makes no sense here, you want to select a few good people for the jury, who then judge the best they can.
This system is still crooked, because most juries have bad taste, are forced to select something likeable or scared to take risks, but in every application artists write exactly what they will do with that money.
edit: I'm tempted to say a good basic income would be a solution, but in e.g. a movie production most of the jobs are not the nice creative ones, so art-house stuff would still need external funding to exist.
This is lottery money, not taxpayer's, but that finite pot of money has plenty of other, legitimate, causes it could be funding.
There is even the curious phenomenon of the 'starving artist', a class of individuals who willingly compromise basic necessities in pursuit of things at the highest order of Maslow's heirarchy of needs. Though few of them are actually starving, really it just means they can't afford luxury goods commonly found amongst even the lower classes.