Activision never promised not to add microtransactions to CTR, it was Beenox (the developers) who promised. microtransactions were most likely a circumstance out of Beenox's control, just like Toys for Bob with off-disc/off-cartridge Spyro content - plus there's no proof towards or against the in-game Wumpa Coin count being decreased so we really shouldn't jump to conclusions.