Well, in total aren't there something like only 5 factories that make airsoft BBs anyway? I remember that Nuprol thread and when I looked them up going after their tracers - turns out the only manufacturer selling their services for .30g tracers are a single company.
Still, I guess it's the same with most simple products. Particularly foodstuffs are typically made in many less factories than one might think - Muller, for example, make most of the UK supermarket's own-brand yoghurt too.
I do like the Guarder .43gs, but they're black and not everyone likes that about them.