That doesn't really fulfill the "quality signal" aspect of journals, though -- the replacement would be some sort of open journal that still had peer review. T

That doesn't really fulfill the "quality signal" aspect of journals, though -- the replacement would be some sort of open journal that still had peer review. There was an Elsevier math journal where the entire editorial staff got fed up, quit, and then simply founded a new journal on the same subject. That's the sort of thing most likely to bring the big journals down, not self publication by individuals. (Well, that or direct government intervention.)