Looked at a 70 Dart GT yesterday

Saw it for sale in the local Buy Sell and Trade, drove out to look at it. The guy mentioned that he paid $4,000 for it, 4 years ago, and the only thing he had done to it was redid all 4 drum brakes. He was an older guy, probably 70, who didn't seem to know anything about the car. So.. I asked what he is looking to get for it now, he says 'I want 15' .. so I'm thinking 'Wow, $1,500, that's not bad' .. then he says 'Yep, $15,000'. Whaaa??? I realize its a bucket console car, with those 1 year 1 model door panels, and that its a 70GT, with hardly and rust.. but its a /6 car, that is starting to show wear. The front windsheild is cracked all the way across, there is rust in the quarters, front fenders, under the doors, and in the inner fenders, and the drivers side has quite a few dings and dents, and the passenger side is starting to bubble. The /6 was old and tired. And.. he almost quadrupled the price within 4 years??
Don't get me wrong, it's a nice car! But am I the only one confused on this? I just can't justify multiplying the price by 4, only 4 years later, without having done any work to it.
























If anyone wants his contact info, PM me.