No one person killed the PIF. There were a few repeat donkeys that couldn't stay away from it. Some of them, oddly enough, seemed to find good stuff to sell on a pretty consistent basis after the PIF got shut down and they were unable to trade their coverless Youngblood #1 for some nice offers.
Then you had the professional scrotum garglers that defended the donkeys and future HOS/banned members actions with their "gee golly, everyone is swell" nonsense every chance they could.
If I remember correctly, rfoii took an offer and offered up cash, and the thread got locked down soon after. So no cash offers should be allowed, because then it becomes a sales thread. I checked in on the thread often, mostly for the lolz, but I honestly believe a PIF thread could work if everyone stopped pretending that value shouldn't matter, as that seemed to be the cause of most of the drama. OP's tiered system would work to solve that problem.