Dismantling, no. What actually happened, is the global market for automobiles drastically expanded from ~1960 forward with globalization and equally dramatic increases in the global median standard of living. Ford and GM didn't get dismantled, they gained a large number of new, competent international competitors that divided up a radically larger global pie.
Further, see: automobile production within the US by Toyota et al. which is vast. That counts as part of the US car industry.
Frontline: Coming From Japan [The Fall Of The US Television Industry] (1992) https://www.youtube.com/watch?v=aesJTsZqm6c