I'd be surprised if we ever see support for Freesync/Adaptive sync in it's current form - aside from the fact Nvidia is currently making a decent chunk of cash out of G-Sync, Freesync/AS is limited in it's appeal due to the current refresh rate limitations on most implementations - something that G-Sync doesn't suffer from. We may see some movement on that if/when freesync monitors start supporting variable rates at the higher end - but the current limitations of 90 on most (and 120 on the top end ones, with tweaking) are a problem
imo. Even then, since AMD are unlikely to be able to support G-Sync, there is little incentive for Nvidia to support the competing tech.
What is more likely is that Nvidia will be able to reduce the price/licence of G-sync which should bring the monitor prices closer together. I've just bought myself an Acer Predator XB271HU so I am a little biased admittedly, but there was a nearly £200 price premium for G-sync over a Freesync equivalent. They really need to get the prices down to remain competitive
imo, I very nearly didn't buy one as a result as it was galling.
Of course the ideal would be that both AMD and Nvidia support both technologies, but thats even less likely than the UK staying in the EU