I don't think it that treacherous.. Lol
In my experience its the product team that decides when something goes into production. That idrive team team may have told the 6 series team that its ready to a certain point and perhaps the 6 series team is waiting on some enhancement (something in the road map) or something else completely to combine at same time of an update. The more pieces the more complex the planning and the smaller the item that can cause a delay.
And we know how Germans like to be precise so until they are sure they are ready, mums the word.
2015 M3 - Mineral White, Sonoma, Exec, LED, Adaptive Suspension, HK, 19" Light Alloy, 6MT ED 7/7/15 - Adrian
2013 535i - Space Grey, Biege, M-SPort, Premium, Tech, Cold Weather, Luxury Seating, PDC, 6MT ED-10/11/2012 - PCD - Greg Poland