You can get the King C Gillette DE blades in the US. Theyre made in Russia though. Do you mean why arent they MADE in the US? That is most likely due to labor cost. With such a low cost item like razor blades, its difficult to find enough profit margin to justify making them in the US. Its difficult to pay the wages and provide the benefits that we expect here in the US and still compete with the labor costs that you would have in countries like Russia, China or some of the other countries where DE blades are made where people work for peanuts with no benefits.
Well, Gillette US hasn't had a blade manufacturing line for 30 years now. Wouldn't make much sense to stand one up for such a low-demand product when Russia already has the capacity.