They can do but they have to bear a lot of cost for doing that.
Bitcoin mining requires a lot of energy. So anyone who wants to set up a mining farm will try to set it up in a place where electricity price is relatively cheap and mining equipment is available at low prices. That's why most the miners prefer places like China, Cyprus where electricity prices are relatively low.
I think he was asking why the USA has no mining machine manufacturers.
Indeed this is what i also understand from the title itself that Mining rigs is what OP is pointing and not the literal mining operations.
I believe it probably does have to do with labour. It also could be tariffs on certain stuff that is required to manufacture them.
Well of course LABOR is one of the main reason because the cost is really high in countries like US and Europe .
and also good point that the Tariffs in trading is considered as well.
But in competence ? US has the resources doing such.