If you want to sabotage an entire sector of the economy, start at a time when the largest cohort of car buyers are entering their 20's. This is when they'll be looking to make their first big purchase. This is also when buyers will begin to form brand preference, even loyalty.
Then offer them crap.
Start with the Pacer, the Gremlin and the Pinto. You know, cars that rust right on the showroom floor. Forget reliability, style, safety and fuel economy. That's for suckers who speak with funny accents.
And if you are "the Cadillac of cars," make sure you coast on your laurels until your loyal buyers die off or are lured away by BMW and Mercedes.
Then, when good sense suggests you invest in breakthrough technology like you used to, roll out big ugly SUVs instead so you can cash in on those big profit margins. Sure, it's short-term profit, but you'll be sippin' Pina Coladas in Boca before the real feculence smacks the ventilator.
Along the way, make sure you outsource as much of the work as possible to places where they have no minimum wage or environmental standards. And don't forget to appeal to your buyers' patriotism with phony "Buy American" ad campaigns. Hell, the rubes will never know that they're SUV was made in Juarez.
Finally, as the city around you dies and people get wise to the crap you've been pushing for two decades, go on a last ditch quality campaign and complain when the buyers you so arrogantly fed shit all those years refuse to come back.
And when they don't come back, and you're going broke, that's when you appeal to the last customer who will listen - the government. And all the taxpayers who got stiffed with a rusted-out Fuckmobile will be forced to pony up for decades of bad management.
Thanks, auto executives. I didn't think it was possible, but you actually pulled a George Bush on an entire industry. Way to go. Make sure you give yourselves a big bonus on your way out.