I was THIS close to buying NVidia for the first time in a decade. But nope, they won't get my money with all of this crap coming to light, especially since I was considering a 970. And seeing NVidia's history (cheating in benchmarks, anyone?), I'm inclined to believe everything bad about them.
Anyway, on the topic at hand... From my, admittedly limited, knowledge on the matter, there is nothing that would prevent NVidia from supporting VESA's adaptive sync. Maybe the hardware wasn't there on Kepler ; big deal, I'd think they would fix this with Maxwell. No, the problems isn't the hardware. It's locking the competition out of their ecosystem. I absolutely hate NVidia for going that route, but it seems it's a viable business solution. People buy NVidia's stuff, so they keep doing what they're doing.
My 2 cents? They should somehow be taught a lesson. It's happened before, it can happen again. But for some reason, I'm not optimistic about it. Many people are so hellbent on buying only NVidia, even when their hardware is inferior (look at 580/680 vs 7970GHz) and are also happy paying a premium for it. I'm not saying "Buy AMD", for all I care they could be doing the same if they had, like, 80% of the market. It's just that the only ones losing (Well, apart from AMD) are the consumers here. We should have had adaptive sync a decade ago (Maybe I'm exaggerating but I don't care), but here we are in 2015 arguing about semantics.