I think you are mixing several issues. I think you are confusing "good art" with "socially desirable art". And the issue of minimum basic income is a seperate one.
1) There is no objective way to tell good art from bad. But there is a way to tell "socially desirable" art from not. To be socially desirable, someone besides the artist has to like it. To take the art I'm most familiar with - writing is an individual act, publishing is a social act. There is no reason you should be paid for your writing unless someone besides the writer likes the output well enough to pay for it. It does not have to be a majority. A really tiny minority could like something well enough to make it worth paying for. Or for that matter even if something is not commercial, some sort of intellectual or academic foundation might like it well enough to pay for your labor in producing it. Or some museum or culture center might think it should be included to give people a chance to educate their tastes. But if nobody likes it well enough to pay for it, not individuals, not an institution, then there is no reason you should be compensated for your labor in creating
it. Nothing to stop you from doing it in your spare time of course. And you probably would have more spare time than in our society. (I can't see a Parecon society in as rich a nation as the U.S not instituting a 30 hour workday with a couple of months vacation a year.) In terms of the social utility of bad are - I think in any society with art, there will be plenty of bad art for critics to criticize and satirists to make fun of. I don't think we need to make special institutional arrangements to encourage it; although our own society has certainly experimented with this.
2) Should there be a minimimum income for peopole without phycisal or mental impairment preventing work (including severe pain) who are neither students or retired, who don't have any of the many other good reaons people might not do paid work? I think probably yes, simply because the social consequences of not doing so are worse than a few marginal cases of parasitism (which would be trivial compared to the parasitism of capitalism). But I think it should be minimal - and not the same income as provided those who work, or don't work but for better reasons than "I prefer to live on the labor of others, and contribute nothing myself".
In an unrelated issue Carrol Cox noted:
>>Just keep in mind that the master himself made a famous pronouncement: "I am not a Marxist."
>
>
> This paragraph is pretty accurate -- there is an old wisecrack that
> wherever two marxists meet three tendencies form. But it is _not_
> correct to use Marx's observation here, since he used it in specific
> reference to a really oddball group in France who called themselves
> "Marxists." It was a chance observation in a particular context, and it
> is distorting to call it a "pronouncment" as though he were laying down
> some abstract universal principle. He wasn't. And it is only famous
> because it is so universally misapplied.
>
> Carrol
The actual application is interesting in the context of this list. The person Marx made this observation about was his son-in-law. And the belief that provoked this comment was something along the lines of what Bill Bartlett and the end-of-work people advocate - that income should not be tied to work. If you are mentally and physically healthy, but just want to lounge on the beach all day, you should still get the same income as someone who works hard producing what people need.