That's not clear to me. I don't know much about things like clothes fashion, but e.g. eyeglass fashion is completely dominated by Luxottica (resulting in eye-wa

That's not clear to me. I don't know much about things like clothes fashion, but e.g. eyeglass fashion is completely dominated by Luxottica (resulting in eye-wateringly high markups) and fashion-adjacent fields such as music are still dominated by just a few labels (this one you can say is basically a product of legal lobbying for protections). The pattern there is that small producers for the most part fail and fizzle out. The few successful ones get snapped up by the big players.