This isn’t overlooked, because the author states as a premise that “all” contemporary artists believe that their works enable many people to feel more aesthetically fulfilled than they otherwise could.

The argument concerns the level of aesthetic fulfillment that many people could have if contemporary artists’ works did not exist; whether people actually want to see art is a separate issue.

The argument doesn’t concern the “value” of an artwork. It’s about whether contemporary artists allow many people to feel more fulfilled than those people otherwise could be. This is a separate issue from the worth or value of an artwork.

This possibility shows that there might be some cont. artist who does bring more aesthetic fulfillment to many people than those people could otherwise have. If that artist weren’t around, many might not have access to art of the particular style/taste that the artist produced.

The argument doesn’t concern whether existing artwork “affects” (changes) the aesth. fulfillment people get from art. It’s about whether, if certain art didn’t exist, people would be able to replace the fulfillment from that art with existing art. Can people find a substitute?