It’s an interesting situation. I can imagine picking up an anthology that promoted Justin Cronin as one of its authors along with several others I’d never heard of. Because I like Cronin’s stories, I’d probably be likely to buy the anthology and read just that story, ignoring all the others.
Of course, the publisher’s probably packaging these unknown writers with a well-known writer in hopes that readers will check out some of the other writers as well. But as I pointed out above, based on my own behavior, it seems pretty likely that those stories won’t get read. But I could be wrong. I recently picked up an anthology of horrors stories, The Blumhouse Book of Horrors: The Haunted City, and I’ve read several of the stories in it even though I don’t know who most of them are. Probably has something to do with the packaging, coming from Blumhouse.
I suppose unknown writers need to fight to make themselves known, and the only way to do that is to keep writing and promoting work.