Back to the spirit of the OPs post, yes I think the fact that adaptive sync is an open standard is irrelevant due to nvidia's proprietary gsync module and the fact that it's a two horse race right now.
Once you've bought into variable refresh, it's hard to go back. Nobody wants to splash out on a horrendously expensive gpu AND a new monitor when they already have a variable refresh display already, and nobody wants to downgrade their experience by losing variable refresh. Factoring in that cost of a new display, regardless of what colour your gpu is, is always going to leave you thinking that you're best sticking with the team you're on, unless the performance delta is really incredibly significant and the price isn't too astronomical.
What we need, and have needed for a long time, is another major player in the gpu market. Intel? Not for a while, mates. Not seriously.