With inflation, they're losing money, actually. Again, perfect examples of why cars are like penny stocks. Every now and then you'll catch lightning in a bottle and look smart. But mostly, no.
At first blush it's idiocy. But then again, plans can change over 38 years. Perhaps he bought it originally as an "investment" or whatever. Figuring it would be like the early muscle cars. But over time, there may have been other plans on the horizon and things didn't pan out as planned. Could have wanted to will it to his grandson/daughter whatever and they're like, we don't want that old car...never know.
Happens all the time. Just think how much it would be worth if it had 156,000 miles on it? Hardly anything. So there are some pluses and minuses. One things for sure, even at $20k, you couldn't build one up that nice for that price