The gsync module is an altera FPGA with 768mb of Ram, cost in bulk is about $25
If nvidia/manufacturer reduced the price difference to say $50 (£30), would that sway you?
I'm not sure how many models you were expecting, they have all the main gamer resolutions and refresh rates covered, with 2 more models announced but not yet released. The rog swift alone has been one of the fastest selling gamer monitors. Ocuk have sold something like a million quids worth of swift's, that is one retailer in one country, and a niche of a niche product, 1080p monitors being far more prevalent. Nvidia only signing deals with a few makers means they are not diluting the market any sooner than they need to, the lack of competiton keeps the prices higher which is good for profits. That is what responsible companies do. That is how they make money and keep paying their employees instead of firing thousands of people in the run up to Christmas.
When there is competition prices will drop. Nvidia could even go as far as subsidising gsync modules if they wanted to/needed.
Youve already paid £200-300 more for your GPU than you could have for equivalent performance, you could have paid ~£250 on a 970 and then gsync would have been "free" (the same overall cost), and you'd have ended up with a better experience overall.