People could all make their own breads, if they had more times, but it'd require more ovens working simultaneously instead of fewer big ovens. It would also take more time for humanity, collectively. And even if everyone had a big oven like those in bakeries, while they could make big stocks of bread for a long time, this would result in everyone eating bread of lesser quality because bread goes bad with time. Having a skilled minority cooking a lot of bread every day in big ovens is just better.
This is not an ode to capitalism or any specific economic system, socialist or communist systems can have bakers to, I guess, tho the ownership of bakeries and boss-employee relationship between them must be rethought or abolished in these cases. All I'm saying is, when thinking up a new and revolutionary economic system, one must always account for bakers.
And sure, robots could bake, maybe. But I don't think they should. Or rather, I think human-made bread and pastries should always exist, because they create variatons and originalities that are interesting. And if human-made bread becomes a luxury commodity and the common people only have access to robot bread, this'd be a tragedy, so better keep the djinni in a bottle and not let robots bake.
Bread and baked goods in general aren't a staple in all cultures. But sure, point taken. Specialization is often a pretty nice benefit of civilization.