The closest thing to evidence is that old rigs in perfect condition get way more than the original cost. That proof is on the auto auctions on TV. Buy it, park it for 20 years and you WILL make money.
As a guy who grew up a son of a car collector, I still cannot fathom why one would want to buy a car, let it sit in a warehouse, look at it and imagine driving over potential resale value.
My dad owns a 2005 Ford GT, it has maybe 8000 miles on it, at least it did last time I joy rode it, and he never drives the thing because he is worried about resale value. He could have had 80K miles on it and it still would have went up in value.
I get buying expensive or rare cars, but not using them in the hopes that you can sell them in the future blows my mind.
As for the Raptor, the last 3 times I've been at the dealership for a service they ask me what it would take to get me out of the Raptor and into a 2016 or 2017 F150. They've basically offered me 55K+ each time. Still have a hard time taking it, but if they are offering me 55k I have to wonder what they intend on selling it for.