I'd say the Chinese sourcing and selling parts for a MOC can be beneficial for the designer in a way. I know there are a few sellers that don't simply send you the instructions, but they ask you to buy them from the author. Then you don't have to source the parts and the parts are more affordable, so the author gets more support. Though most stores simply send you the instructions, so the author doesn't see any reward for his hard work of creating the instructions.
Then there are brands like Lepin (now King and Queen) that also copy Ideas projects. I believe the designer receives 1% from total sales of that Ideas set from Lego, while they see nothing from clones.
