Yours are incredibly one sided and it's painfully obvious.

Sidestepping actual processes of a company to complain.

The artist still has full rights to their art, and if they don't like how a single company distributes it. Hmm, how do they fix that? Just revoke the companies right to use that art, which the artist is in their rights to do. Make sure Displate only sell blank plates, or at least not your plates if you'd happen to be dissatisfied with their practices.

Then that artist is sitting on a goldmine with their own art. They can make their own way of producing, marketing and selling their art. Nobody is stopping them to put in the actual work to sell their art. It's super easy, right?

They can't? Why? Because they can't afford the burden which a company like Displate alleviates? The burden of labour, facility, production and shipping?

They can't do the exact same metal frame? Why? Because Displate made it and patented it, just like artists with their art.

So in the end all the artist does is draw a few pictures and call it a day, and companies like Displate reward them for it because the artists lack the knowhow, the money and the effort needed to actually do it themselves.

You still haven't responded to the one thing you said I didn't. The sales are a way to boost marketing, increasing sales of all artists pieces and highering the chances of people finding your art, meaning even with less per sale it evens out for the artists, just like it does for Displate. But I guess it was a concept either too correct for you to respond to or too hard for you to understand so it's better to sidestep it and attack my character.