Your opening about supply and demand is a very interesting and thoughtful comment. High supply usually translates into lower demand and therefore lower value (it's not a foolproof measure, certainly, but it's generally pretty common). It goes to the heart of economics, the "dismal science."
I can't speak for your experience, but I was brought up with the same beliefs: you're out there on your own battling against the hordes and elements, and if you want something you'll probably have to compete for it, especially if what you want has some sort of intrinsic value or is in demand. It could be that dream job, it could mean that perfect mate, it could mean that airline seat during the busiest time of the year, etc. etc. The list is almost endless.
But we know that, as you suggested through your "horn of plenty" metaphor (nice turn of phrase, by the way, I quite like that), the very stuff we seek comes essentially from nothing. (Physicists who wish to argue the point, please line up to my left.)
It's a very difficult mind-set to break, however, towards idea of abundance, especially when it's been drilled into us since we were wee tots that anything worthwhile demands competition.
I don't have any tried-and-true methods for completely changing this mind-set, but there is one way I've found which goes at least part of the way to grasping back some semblance of control.
How we think is reflected in how we speak, and how we speak can modify how we think. To that end, I very seldom use the phrase, "I can't afford that" anymore when there's something I'd like but find myself a little short of $$. Now I make a conscious effort to say (or think), "Spending $X on that isn't a good use of my resources right now."
That does a couple of things:
- It gives me back at least a semblance of control. After all, if I really REALLY needed whatever it is, I'd cash in some savings or sell a kidney or hire myself out as a freelance doorstop;
- I'm not denying myself the pleasure of the purchase and ownership of the item entirely, I'm simply delaying gratification. It's not that "I can't buy that" it's more, "I'll get that at some point in the future when my financial situation has improved."
I've also come to the conclusion that I really don't need, say, 32 pens in my desk or a cluster of magazines that I never look at or dead batteries that look perfectly OK. When in doubt, throw it out (or give it away, or donate it, or something). Just having less *stuff* in my life tends to keep my desire to attain more *stuff* in check. Not sure why that is, but it works for me.