Hard to make sense of this. Japanese cars cost more than their US counterparts - compare the sticker on a Camry or Accord to a comparable US model and you'll see. Not only that, they don't offer whacky incentives like 0% financing and "employee pricing". Toyota, Honda, and Nissan build cars in the US and Japan, and they make more money per car than Ford, GM or Daimler.
Also, what subsidization are you speaking of? The Japanese government isn't subsidizing the Honda plant up the freeway from me, it's 20 years old. Or the Toyota plant in Georgetown, KY, about 80 miles south of me. GM and Ford are the victims of their own bad products, ridiculous brand structure, and UAW legacy. Fear of decisive action has brought GM to this point. Buick and Saturn should have been shuttered 5 years ago, along with Oldsmobile. GMC has never made sense as a brand.
BTW, I have one GM vehicle, an Envoy. It's a piece of crap. The radio coating peels off constantly - I'm on my third radio. I gave up putting in new ones because it was a hassle to be without the car for the day. Door and window seal trim fits poorly and falls off. The rear doors must be slammed with the might of Superman to close properly. Great car. These are things that other car makers - my wife's Chrysler Town & Country has been trouble free for 6 years - have long ago conquered. With GM, anything you buy is a gamble, as Kerkorian learned the hard way.
Last GM I'll ever buy. I hope they go bankrupt.