Time will tell, but I can't see any reason to doubt whether this could scale. As long as an artist can inspire intense loyalty from a small group of fans, they could forseeably supplement their income with donations. This won't work for all artists, and won't replace existing funding models. But there are a lot of creators who fit this bill.
I, for one, and excited to see crowd-patronage grow. It's a model that rewards artists with cult appeal (versus the consumer model, which values mass appeal). The arts will be a little less bland.
See my other reply that's like a great-great-uncle-once-removed of this comment or something, and I'd highlight I'm using real numbers from my real patronage, not theoretical things that could happen someday.