there is 1 reason why American cars don't last longer than Jap crap , because they don't have to, we will all still buy them ! stuff was made to last back then, and stuff today is made like crap. those engineered steel (tin foil) panels, throw in a rust hole and lets see how it stands up !!!!!!!!
as for american cars leaving you ever heard of Auburns, Cords, Duesunburgs, models T's and a hole list of others
now some sell for Millions...........