I hate that logic too, and when I fly international it can amount to many hundreds of dollars. (Admittedly I've never done it, instead I focus my energy on researching the best integrated multiple-airline or "hacker" fare instead.)
However I think I managed to come up with an analogy that does explain the airlines` perspective: I am a professional photographer, and my daily rate's "list price" is $600. Sometimes I get that rate, sometimes not. Let's say I had a slow month and gave a client a great deal - $300/day - and he prepaid but never showed up. That's fair since he paid... but if he does it 10 times in a row, at some point I'd start wondering if I'm losing revenue and my ability to book higher-paying gigs because of that behavior.
Really, any service or rental analogy would be better than logs of wood since we "rent" that seat and time on the plane, we don't take the seat home (especially with Y chairs, who would want those).
To clarify, I still think the airlines fare system doesn't make sense. For most of us any ticket is always a "promotion" so the logic where more product correlates with a higher price has been long lost. Even renting a 2BR is way cheaper per bedroom than a 1BR, but it's still more than a 1BR rental overall. The market doesn't allow otherwise.