We bee keepers know differently! And we are all experiencing dead hives. The "no conclusion" stems from the fact that there does not seem to be one factor (cause) that we can point to. I can tell you that 2 winters ago we lost almost 40 hives. We had absolutely NO Nosema in those hives, as we send samples to the state lab for testing. They did report that we had a higher than usual Varroa Mite count. Yet other apiaries report losses from Nosema.
There seems to be several causes and they many times overlap..... GMOs, neonicotinoid pesticides, Nosema fungus, Varroa mites, hive beetles, and other pests, and stress from transporting them long distances for huge pollen purposes.
Please don't be so flippant in dismissing this very real problem as a non story.