We've been doing it for genetic modification for ages. If it's possible to stop people from making human-chihuahua baby hybrids en masse, why is it impossible to stop people from culturally devaluing art en masse?
I don't think it's reactionary to have a cultural concern like this, either. Especially when the concern boils down to hyper-commodification. I'm not concerned about some abstract "rot" of society, but rather the commodification of art itself.
How do you propose to do this, mechanically speaking? Who would enforce such a law, and how?