I don't care if you disagree with my opinion, but you are missing the point.
I see your point but I disagree that you'll live long enough to see much return on your investment. You have to really look at the economics of the situation. If you get a
mint '67 F-100 4wd 4-speed for free or pennies on the dollar, absolutely, you know that you've got an "investment", because you're absolutely sure that you can flip that truck for considerably more than the cost to you.
BUT, if you -like a lot of us, I think- pick up a truck that needs considerable mechanical and cosmetic work, you can
easily put in 10 or 15k dollars getting it up to show status. And "show status" is absolutely where one of these trucks has to be in order to bring home some money. The thing is, if you put 15k bucks in to bringing one of these trucks back to concours condition (probably more than that for concours), you're still going to be hard-pressed to turn it and get that much money out of the sale. Even if you do get the sum of the parts value back out of it, I'd bet when you factor in labor you won't break even
Granted, all of this is me talking about the average guy looking to buy a truck. I realize that there are people out there that are
really good at flipping cars, and can recognize just exactly the minimum amount of work that needs to happen in order to squeeze out the maximum profit. If you're one of those folks, more power to you.
Just because it's old doesn't mean it's desirable. There are plenty of cars and trucks built in the '50s and '60s that are worth bupkis now. I can't see that bumpside F-100 4x4s have a special place in the hearts of a significant number of individuals, and THAT in combination with rarity is what makes a classic's value go up; you've got to have some cachet with folks that have $$$ to go along with low production numbers, otherwise you just have an oddball that's not worth much money.