The 6000 SUX represented everything that went wrong with the "future Detroit big 3". Apparently in the Robo-Cop universe, the Detroit 3 (assuming the big 3 were still around, judging by the police vehicles in use at the time) continued to produce large, clumsy, gas guzzling vehicles and as a result--contributed to the demise of the city's infrastructure faster than it did in reality---possibly as a result of poor sales. A parallel could also be drawn from Robocop's version of Detroit and GM's decision to pull out of Flint Michigan.
Ironically, the movie's time scale (mid-late nineties) didn't match what the writers had in mind---considering SUV sales started to take off circa 1998. It wasn't until 2007 rolled around when we started seeing the dystopian situation develop around the Big 3 that it started to mimic what the writers envisioned in the movie.
Ordinary