It's absolutely true, he's trying to get Valve to buckle so he can stop spending money on exclusivity deals that are absolutely draining them. And that 12% is barely enough to keep the lights on, and the bigger you are the more extrapolated your costs are going to be so it's not even a consideration for Valve.
They're going to hold fast and do nothing and watch his investors eat him alive which they're probably already doing, he likely promised them they would have caved by now. Tim is fucked, EGS is fucked, it's unsustainable and they're falling like a house of cards.