Wouldn't surprise me if they implemented an element of cost to the program/benefits at some point. Avios are now based on cost right? And CK they say is primarily on revenue so its not atypical. E.g Membership at 5000TP or £50k spent, renew at 3000TP and £30k spent or something like that. I'm not saying I'm an advocate of the change, but it's one way to stop TP runners/BAH GGLs etc. if that's actually of concern to the powers that be (I personally don't think it is).

They should have called GGL the Concorde Club or something.