I don't think that's completely true. For instance, one of France richest man, François Pinault actually owns a very large collection and hosted a large exhibition in Paris at the Bourse de Commerce. It's not only him, Bernard Arnault, actually the richest man in the world also made a lot of things for art, craftmanship etc... Of course, like you said it's mainly investment and "art-washing". I don't know how much this thing is going for more modest patrons, but I guess they act on their own levels, locally.