Since communism isn’t illegal in western countries, and there’s literally nothing stopping a bunch of comrades from starting a business where the workers maintain control over the means of production,

Yes, this is called China, Vietnam, Laos, Cuba, North Korea, and the former USSR (and many others)

E: also not being snarky, mondragon and basically all co-ops are working as you suggest. Did you not know what a worker co-op was??