It seems to always happen when a vehicle is around 30 years old. I think it happens for two main reasons:
1: The previous body style is now too expensive so people move on to the next best thing. All the magazines, builders and collectors are going after squarebodies at the moment, so regular people are starting to look towards the OBS. It's like with Corvettes. Everyone hated the C3 and C4 until the C1 and C2 got so dang expensive that regular guys can't afford to buy and build them in the current market. Now the C3/C4 is not so bad anymore.
2: Nostalgia. Cars become valuable and popular when the people who remembered them as kids are old enough to have disposable income. Right now 80s and 90s cars are popular because 80s and 90s kids are all 30-40 years old and finally buying the stuff that was new and cool when they were young.
I was born in 1993 and my favorite "warm fuzzy" vehicles are our trucks and 80s Honda dirt bikes. My dad had a '92 K1500 when I was a kid, and when I got older a '86 Honda TR200 was my first "car".
And you know what's on the top of my short list of "If I see a good deal on one I'll buy it" cars? A RCSB gmt400 and a XR600.
