I guess I could describe this situation from a personal historical POV.
Back in the day when I was a wet behind the tea bag over-driven hormone factory, the only cars that put a gleam and a tear or two in my peepers were all American made iron. Cars like the 'Vette, (yeah, I still own one), 'Cuda, Z-28, Boss, RoadRunner, 4-4--2, hell, even the Javelin looked good to me back then, were all I craved for.
To this day I still crave for cars like that, but Detroit, starting from the late 70's onward did things that changed my outlook on the products they were pushing on us. Wether it was an insidious attempt at a grab for more of my $$$ for much less return in value, or Detroit losing sight of what my wants, needs and desires were for American iron, or the fact that I started noticing the foreign imports becoming more appealing due to their better inherent longevity, reliability and resultant resale value and "ego" appeal, I've never really ruminated about.
All I know is at this very moment I know what I want, and Detroit ain't making it. (well, other than the newest 'Vette).
In my view, Detroit still makes unreliable, short-lived products that break down too often, rust too fast and cannot sell used as well as the imports (or their domestically manf'd versions).
Here we have in some cases, different branded cars, made in America by Americans, yet it's the ones with foreign decals and insignias that are grabbing majority market share. So it's not who actually assembles those cars that decides which manufacturer I buy my product from, it's the overall philosophy and smarter decision making being done by the car maker's Management that's doing it.
I see where the Big Three is gaining ground on the competition, and maybe we actually are in a period of favorable transition for them, but when the economy collapsed, it exacerbated the miserable condition the Management of the Big Three put themselves in.