I agree that old trucks are a hobby and that thinking in terms of profiting on them isn't realistic for most people. But to consider economic impacts in deciding which way to proceed on a project only makes sense for any of us with a finite amount of money.
Because modeling the financial impact of projects has been a significant part of my career and because I actually get a kick out of being able to 'see further' in doing it, I probably go too far on some of my projects.
When one of the two most common arguments I hear advocating Diesel motors is economics I feel it's appropriate to respond with an economic model. Especially when that model shows some of the supposed savings are an illusion.
One model I did and then ignored was comparing buying a finished truck against building a shop to build my own truck. It came out the way my wife expected: we could have bought a couple of very nice trucks for less than I spent building my shop.
But to me one of the most rewarding parts of the hobby is doing it myself, and that requires a place to work. It also consumed enough capital that I have to consider a little more carefully what I spend on the projects because I spent so much money on the place to do it.
Yes I can sell the shop someday and recover what I spent on it, probably at a higher rate than any of the money spent directly on trucks, and maybe even at a gain, but that financial transaction is meaningless to me because I intend to die owning a shop.
While it does not make real economic sense when you look at the finished projects, what I've bought is the opportunity to experience the did it myself satisfaction. And that was worth the money to me.
