I'm not a fan of Steam for their Hardware Survey. But maybe that's just me.
I don't move in rare circles, but I am on most HW forums and in lots of gaming circles (though under one of my multitude of names). So I get a little bit of a pulse on what's out there.
Its still going to take time, but it will come, at least I believe it will.
I would also be inclined to believe the Steam hardware survey. 1080P and even lower resolutions are still mainstream and the most common resolutions encountered. 1440P and 1600P won't become mainstream until they can come down even further in price and have hardware provide similar performance as 1080P at 1440P or 1600P resolutions. I've had a chance to try 1600P (albeit in some stores) many years ago and I still haven't seen 1440P/1600P achieve mainstream status. Enthusiasts make up a very small niche market and percentage that even if the percentage was to increase it still wouldn't compare to the prevalence of 1080P. For example prior to me acquiring my 1152P monitors I ran 1080P and prior on a 4:3 1280x1024 LCD monitor.