Epic is, hopefully, working on light propagation volumes. Which is just about the fastest actually “global” global illumination technique available, and its shortcomings, such as lacking GI to and from distant areas, can hopefully be overcome.
The problem with just about all the papers you linked are… well all realtime GI has multiple problems. It’s an NP Hard or rather O(n)squared problem, meaning there’s basically no way to really hack around it and just make it fast. And so there are tradeoffs, like excessive light leaking (which doesn’t look good) static environments only (not ideal for many reasons), lack of specular information (really not good with UE4’s physically based metals) and etc. Including usually “it takes up a heck of a lot of time.” I don’t think I’ve seen a game use absolutely any of the linked papers, often for multiple of the above reasons and others.
LPV is nice because, while there’s light leaking, if you’re clever enough you can make it “manageable” to where it’s not too bad. And there’s a lot of other tradeoffs, not really workable for highly dynamic objects, light has a “latency” or rather the GI has lag time, and etc. etc. But for most game scenarios it’s a “good enough” solution. And since GI is so hard (literally by definition) “good enough” is about as well as we may get done for this entire generation.