Agreed thats a lot of money to be asking, that being said...................
I have heard "some" parts were sourced out, not everything as you indicate. Some of the Enfield purists give them a bad rap but I'm not sure if that's grounded in factual information. There is a lot of miss-information floating around about these AIA rifles.
One thing I can tell you is they are very, very well made, the machining is very nice, fit and finish are great and they are accurate and highly sought after, junk does not garner much interest and have much of a following! If per chance they were completely made in Vietnam as you indicate then my hat goes off to the Vietnamese for making a very, very nice quality rifle! Yes they are expensive and aside from the quality, that's because there is a limited supply floating around and the majority are in .308 cal which makes them desirable.