Owning cars is both a decision made of desire and money. Desire because you buy what you want. Money which is a balance between what you are willing to spend and what you want to get out of it financially in the end. The balance of these two is always a struggle.
If your interest is only money, you buy cars which can be bought and sold for profit. If your interest is only what you desire then profitability does not come into play. I think most of us fall some where in between.
It would be nice to buy cars you can put some money in, drive, sell and make money. That would be a perfect world. For many of us building and creating a car makes us feel like we have created something that is our own. If I go out to a golf course, at the end of a day, I feel it is a day wasted and I have nothing to show. If I go out and build on a car, at the end of the day, the week, the year, and eventually the end of the restoration, I have something tangible I have created, with my ideas, my desires and is mine.
Money well spent? Often no. At the end you have a car worth less then the $$ put into it even without the labor. Quite often, people either hate their car when done, are tired of their car, or are already dreaming of something else when done and sell the car at a loss.
Is the money spent that bad? It depends on your situation and your life interest or goals. Some one who just want's to keep it running has different goals then some one with grandiose ideas of creation. Me for example. I am finishing up a restoration of an MGB which will take me a total of 3 years and $30K when done (plus $5k prior value). What will it be worth? Probably $15-20K. If I sell it I am loosing say $15K. That comes up to about $400 per month. How much are green fees for golf? How much are movies and popcorn I missed? etc.
I don't ever plan on selling the MGB but it is my work, my idea of what I want and it's my creation. What is that worth. Here is the construction website:
http://www.rc-tech.net/MGB/Gary