If your reply was sarcastic (can't tell) :-) Say those products are "designed" over here but built in China/Taiwan/Korea. Alienware may be a American company, but it certainly doesn't make 100% of the components in the USA. Perhaps one or two companies (say PSU) are 100% British, but component wise (transformer, resistors, capactors, PCB etc) made abroad.
If products were 100% locally made you can bet price tag won't be so low (quality will be inferior also)