Yes, I'm sure the next-in-line elite would naturally seek me out and thank me for opting out of my upgrade. Or was there some other sort of "appreciation" I should expect from my fellow elites?

I'm reasonably sure anyone who I ask to swap my FC seat with will appreciate my generosity, Elite or not. And it's much more likely that I'll get the pleasure of a sincere "Thank you!" from the displaced passenger than a show of gratitude by any Elite should I elect to follow your "rules" instead.