Have you actually been inside many warehouses or factories? I don't think I've ever seen one that was as clean or visually attractive as the areas that customers were meant to see. You're right that they're (usually) not filthy to the point that it impedes operations, but it's quite correct that customers don't care about how the warehouse looks like as long as the goods arrive on time. Same for restaurant kitchens, bakeries, metal workshops and a host of other production facilities. The only production facility I've ever seen that was "clean" was the assembly area of a medical instruments producer (it was a literal clean room with suits and everything), but even their warehouse did not look attractive. Their customers were quite happy though, the company was growing fast.

Most programmers imagine other industries to be better because they only see the customer facing parts, but that is like judging the state of a codebase by how nice the landing page is styled. Penny-pinching managers exist in all industries.