They might could pull that off with Zen solos, because they could just make Zenpool yield at a very low rate. Primes, however, can mine for real pools out of the control of GAW. And the maintenance cost will never go up. So, if the price of BTC goes up, thereby reducing the cost of maintenance in BTC, there's not really away to avoid payouts for primes. So people may just never want to sell primes.
Nothing at GAW mines in real pools. They all mine in phantom pools on phantom hardware that may, but most likely does not exist. The rates are just posted for reference so customers can feel like they are really mining, not just getting some bitcoin everyday based on the posted rates. Those are also at Gaw's discretion and if they decide Primes can only mine on Paycoin and nothing else then you are stuck with that. They are trying to force everyone to upgrade to Cashtakers to they will have almost nothing to payout in bitcoin and they can pay everyone in their shitcoin XPY.