Congratulations class of ‘68— the oldest used car in his lot is a ‘63. There’s even a ‘68 in amongst the late model used cars, mostly ‘66-‘67’s. He had a good buyer at the auction, or really loyal 2 year flippers. My dad would get nervous as 50,000 miles approached. Seems like when they were $4-5,000 you had more room to get one more often, even though wages seemed commencerate with prices.
When I was a kid many families who made a decent living, would buy a new car every 2 years. Trade the old one in that probably had only 20-25,000 Miles on it, add sometimes as little as $4 or $500 hundred and get a new one. Chevy's back in '68 were only about $22-$2800.
Plus I think the really successful car salesman stayed on top of the guys you’re talking about. I remember my dad bringing home a few demonstrators (not the hippies for Humphrey type) in the late ‘60’s about trade in time. Seems like they had the margins to swing those type of deals. I bet even with their car and $500 the dealer still made a few bucks.