I would argue a fast food kitchen (or any kitchen) is a factory. An incredibly efficient one at that. Things are made and assembled to order from intermediate components.

We take it for granted the amount of labor that goes into our food. There's no reason we could not make other consumer goods in the US at such scale - we just have weird, self-imposed constructs that say assembly line workers get more prestige and protections and food workers don't. Or that we are willing to pay $8 more for a nicer version of a meal, but we won't pay $5 more for a nicer pair of flip flops.