Even if Freesync is not mainstream yet, it doesn't really matter much because frankly G-Sync itself has not proven to be a good enough alternative for the following reasons:
1) It's available only in TN panels, and out of that already small selection of monitors, there is ONLY 1 monitor that is even good -- the $800 Asus PG278Q 27". Are you kidding me? The price is too high and the screen size is way too small for many of us who have been PC gaming on larger LCDs/30" monitors and Plasma screens for 5-6 years. When 27" Korean IPS 2560x1440 monitors go between $300-400, $800 for a TN GSync monitor is just appalling even from a prestigious brand like Asus. :whiste:
2) We all know that 4K is the future so buying a 2560x1440 $800+ panel only to replace it in 2-3 years with a 4K monitor seems like a stop-gap solution. There isn't a single good 4K monitor with G-Sync yet. And even when it comes out, if 27" TN 2560x1440 costs $800, how much will the 4K G-Sync IPS one cost?
3) G-Sync => So you spend $$$ and lock yourself to NV for the useful life of a monitor which for most of us is 6-8 years (!!!). Not sure if serious. Maybe NV will produce the best GPUs for the next 8 years but maybe not but buying a G-Sync monitor more or less means you
will be paying more for every single GPU upgrade for the next 6-8 years since you don't have a choice buying AMD. For example right now I can buy 2 used after-market 290s for $600-700 vs. buying $1,200 GTX780 Ti SLI that can even be
much slower, which is unacceptable. Can NV guarantee that for the next 6-8 years they'll offer very similar price/performance to AMD every generation or if I am paying a premium be faster in every single game? Nope, they can't.
#1 and #2 should be addressed over time but not #3. I really have a problem with being locked into 1 vendor, especially one that overcharges for their products and the price increases have only gotten worse in the last 5 years. I want an industry open standard so that I can pick and choose what GPU I want to buy.