While I cannot claim quite the same scope of being a hunter-gatherer of automobile stuff that the author describes (17,000 SF? Really?), in my younger years I was always on the lookout for any part from any brand that was factory genuine and was or could be made serviceable. Dollar profit never even entered into the decision making process, or at least until it was time to stop being an active gearhead. I was motivated by a bigger reward.
Trade bait.
I originally caught on to the concept when hanging around old school hot rodders who damn sure knew exactly what they wanted, but few of them had the disposable income to go retail. Instead, unneeded but good quality used stuff was horse traded for something that was needed and everybody came away happy. In addition, an extra benefit was you often became friends because who doesn't want to have friends who have proven themselves trustworthy and won't defraud/deceive/screw you over a stupid car part? I mean, you got the part needed for the affordable price of giving up something you no longer had a use for and potentially made a life long trustworthy friend who has a similar interest in things that are loud and go fast. In my world, that is a home run compared to mere profit getting no further than first base.
As most everyone on this forum who builds what they drive, fixes what they break, or knows the satisfaction of resurrecting something from the DMV graveyard, sourcing a desired (and may I confess, sometimes lusted for) correct part for our special vehicles can be an expensive and frustrating tedious **bleep**. Yet it never failed to amaze me how an object that could be had for $25 back in the day is now not for sale at any price, unless you dip into your stash and offer some similar treasure in exchange. More than just transactional, and a lot more fun than slapping down a whole bunch of Benjamins.and secretly wondering if it was really worth it