The thing is, people expect them to be like sports cars, that's the thing BMW and other companies have done. They're more of a progressive, sporty, quality, brand, whereas the sporty brands of the Big Three, Mustang, Camaro, and Challenger evoke a legacy and perhaps something more personable than a German sportscar.
I think what would really aid The Big Three is reducing costs, focusing more on the quality and build, around 75% of their labor is done by hand, which is too expensive and, considering their attempts to try to cut costs around this, lead to disastrous results for them in the '90's. In turn, this would help ease their reputation to be from "I need a car that can be shit and Ford makes the cheapest shit" to "I want a reasonably priced car that is well made, Ford/GM/Chyrsler can satisfy that more easily in one package than say, a BMW, etc."