Well, poor literature has always existed, which some might not even dignify to call literature. Are writers of such things threatened by LLMs? Of course they are. Every new technology has beought with it the fear of upending somebody's world. And to some extent, every new technology has indeed done just that.

Personally, and... this will probably be highly unpopular, I honestly don't care who or what created a piece of art. Is it pretty? Does it satisfy my need for just the right amount of weird, funny and disturbing to stir emotions or make me go 'heh, interesting!'? Then it really doesn't matter where it comes from. We put way too much emphasis on the pedigree of art and not on the content. Hell, one very nice short story I read was the greentext one about humans being AI and escaping from the simulation. Wonder how many would scoff at calling art something that came out of 4chan?

Maybe this is the issue? Art is thought of as a purely human endeavour (also birds do it, and that one pufferfish that draws on the seabed, but they're "dumb" animals so they don't count, right? hell, there's even a jumping spider that does some pretty rad dances). And if code in a machine can do it just as well (can it? let it - we'll be all the better for it. can't it? let it be then - no issue) then what would be the significance of being human?