I don't know about that...it lasted at least a decade, and keep in mind the average age of a car on American roads in 1979 was 5.7 years, and that was up from a lower figure in 1969. A-body Mopars happened to be more durable than many cars of their same build year, so -- just like the owners of rear-drive Volvos and other especially sturdy cars -- we tend to wear out/use up stuff the average driver never has to think about. We wear out dashboard chrome. We use up ignition keys. We wear out windshield lockstrip mylar. That doesn't mean the original stuff was crap, it means our cars lasted way past their stint on the actuarial tables!
(the 2013 figure is 11.4 years..."they don't make 'em like they used to")