I know you weren't talking about "FICO self-destruction by a million inquiries" as being irrational. I was just saying it was the only situation in which I thought bonus hunting was irrational (along with bonus-hunting for people who spend so much that they'd hardly notice a bonus, *or who just want simplicity*).
I spelled out my views on nerfing pretty well here in my first post:http://creditcardforum.com/rewards/11114-nerfing-lifecycle.html
In summary, apart from no-AF very boring cash-back cards, nerfing seems inevitable and intentional on every card. Nerfing seems to usually be part of the plan when an issuer creates an (initially) great card. As you pointed out in that thread, QuickSilver and TrueEarnings survived from nerfing, but they weren't exciting cards to begin with.
And if you think consumers should cooperate, then you might want to consider going back to cash or debit. The vast majority of merchants charge the same prices to credit customers as they do to cash/debit ones. We credit users are driving up consumer prices for everyone, after all - especially with Amex, Visa Sig, and WMC/WEMC.
*As I see it, it is up to issuers and merchants to set the incentives, and up to each individual to decide how to respond. I don't think of the situation as one where I'm harming other consumers. I think of it as one where the issuers intend, from the start, to water down the rewards and give little value to the consumers that hang around too long.*
**To continue the economic theory theme, I look at decent-or-better AF cards, and every single one of them reeks of what could be loosely called planned obsolescence. Issuers couldn't make much money if a card's terms (and the rewards program behind it) remained great forever. They count on customers not completely realizing it when a rewards system is no longer worth it, and continuing to spend/pay AFs, despite getting little value.**