It's very difficult to trademark things that are freely available to everyone. Colours/numbers/etc...
Trademarking not usually done willy nilly...and resolutions in court are not the shortest things most times. If you think you can...go trademark the shape of a sock...let me know how that goes.
A lot of "stuff" is made overseas because of labour costs, less legal/environmental/oversight/regulation requirements, etc... Stealing someone elses design is possible because of the issues with pursuing it legally internationally. The only reason a corporate entity does not pursue legal action against trademark infringement is that the costs of doing so exceed whatever benefit they would derive from it.
i.e. (making up an example) I can't see LaRue pursuing a knock off shop in Asia for making ACM clones of thier mounts. They certainly might send a cease and desist letter...but chasing it through the international legal system is probably a non-starter. However...if KAC ripped off their designs and started producing it, there'd certainly be a court case.