I still consider myself a bit of a 'newbie' when it comes to the history and knowledge base about AMC's and Eagles, but I am old enough that I was shopping for cars when AMC was still a company. (I bought my first car in 1984-85). I also owned a 81 Spirit before American Motors was bought by Chrysler.
I noticed even back then, alot of people I ran into had nothing nice to say about AMC. I found people were fast to drop the cars then. I know this is redundant, but I noticed it back then where I grew up.
After AMC was folded into Chrysler (into the early 90's) where I'm from, you couldn't give away an AMC unless it was something like an AMX or a 'Machine' - Something really rare or sought after. Even still, they didn't fetch the price they do now.
So I'd say the first 'die-off' I noticed is just before AMC was sold. It wasn't really a die-off, but sales and interest did decrease. Maybe that is more accurate. I did notice in around '86-87, that people's interest was lessened.
But the real 'die-off' was just after AMC was sold. After that, I'd say into the mid to late '90's.
It's only recently, that the asking prices and interest in the cars have increased.
As a side note...
I find that soo strange, because as the cars get older, and the parts get harder to get, the cars are worth more??? when 15 years ago, the cars were still newer, had more life in them, less abuse and neglect, you could still buy most of the parts, and people couldn't wait to get rid of them.
Buying trends are weird...