I'm pretty sure I read somewhere that updates pushed to the phone are actually by choice of the service provider and has nothing to do with HTC. So really we're at the mercy of AT&T ,T Mobile ect(Straight talk for me) The Vivid is more than capable of handling the updates. I feel they are doing the same thing Microsoft did with Windows XP, to encourage tossing the old and buying the latest money maker. My single core processor & virtually no ram pre-paid ZTE savvy had Jelly Bean, yet dual core 1 gig ram vivid can't?
While reading through CM forums for unrelated reasons, something stood out to me that I saw a bit of relevance in.
" When you get devices that have Sense or Touchwiz like interfaces, the code is no longer viewable to CM, so they have to start guessing and writing hacks to try and get the camera that was designed to work with Sense to work with AOSP. As I said earlier, this is sometimes extremely hard to do (with the HTC One X, they had to do hacks to prevent the face detection from running, otherwise it would crash the CM camera app - they were never able to figure out any workarounds)." ~ bassmadrigal. From this forum.
http://forum.cyanogenmod.com/topic/76294-htc-vivid-holiday-cm10-confusion-revelations-and-feedback/ Which tells me that if the amazing developers for CM can make kitkat/JB work for vivid even while being ball and chained by locked closed source drivers. Then Making a legitimate KitKat (RUU?) manufactured ROM is more than possible. They're just big meanies