@Gen : Yes I think Arnold but don't count out Vray , is the main cause.
I am not 100% sure but I have a feeling that Arnold was/is gobbling up their marketshare and they have underestimated Vray for the longest of times as well, so let's hope for them that this works and that it is not to late as people tend to finalise their pipelines at a certain point ( and from then it takes along time to convince people to use something different)