There were 16 million new vehicles are sold last year in the US and there's 260 million registered vehicles on the road with a median age of nearly 12 years old.
To say that there's "tens of millions" of perfectly operational cars on the road in the US is really an understatement.
For Toyota ~57 million vehicles from '02-'09 https://www.toyota-global.com/company/history_of_toyota/75ye...
For Honda ~23 million from '02-09 https://www.statista.com/statistics/267276/worldwide-automob...
Volkswagen group looked to be in between the two.
Didn't look for Ford or GM.