As a frequent Gear VR user and someone who tried more than a dozen of different VR (and AR) headsets, I am quite convinced VR will become widespread only when BCIs become good enough. Enthusiasts like me are excited for VR but most people are not. Really. It's impossible to point exact year like, "2019". When we can control computers with our thoughts with more precision and ease than with a keyboard and a mouse, then VR very rapidly may become ubiquitous. There will be no such thing as mainstream VR without BCI. I would even argue that what we have now is not true VR. It's just a box you strap to your head and use a Wiilot or two with it. Even with 2160p screen you still can see every single pixel.
What needs to change for VR to become mainstream and "make a real comeback":
- comfortable thought control much better than more traditional controls (like Kinect, PS Move or gamepads)
- thousands of times faster GPUs (without increasing power envelope)
- at least 180 degrees field of view
- small (and cheap) displays that have more than 100 million pixels
- super advanced game engines that allow for easy content creation (in VR using AI), without the need for thousands of people to work years for a single project (like a game)
No idea when it will happen. 2021 would be perfect but it is only a wet dream. BCIs and FoV like that may be realistically available by 2025, displays by 2026, game engines by 2027 and GPUs by 2028. That would mean comeback around 2030, 13 years away. Most people I talk with, consider VR a gimmick. I know some who use it on a daily basis but they are exceptions, they were always interested in stuff like that, just like me or Palmer Luckey (he's a hardcore genius). In my opinion, every one of those things must come to fruition before VR sets become like smartphones today. And honestly, I am rather disappointed with last 4 years of development in virtual reality. I remember using Oculus Rift in 2013 and not much has changed. For 1200$ (which in many countries is a huge amount of money) or more you get blurry, pixelated experience with extremely limited controls. Sadly, you can count good VR games that are not demos on fingers of one hand. Hardware is limiting software and software is limiting hardware sales which is limiting hardware R&D.