Is it written anywhere that the 1DX isn't using this technology?
Nor is it written that the 1D X doesn't use clairvoyance technology to pre-focus exactly where the action will take place. If it had a BSI sensor, Canon's marketing department would make sure everyone from the president of the USA to the rats in the sewers of Calcutta knew about it...
Does Canon trumpet any particular patents when the release a new lens that is covered by them?
Or does any other camera manufacturer?
Given all of the patents regarding specific technologies in cameras, do any of them get trumpeted?
What do you think is more important for marketing: BSI or how many MP?
What do you think the average Joe on the street that walks into a camera store cares about?
actually Canon does trumpet newly patented lens ideas on lenses all the time. remember the big deal they made over Hybrid Image Stabilization (H-IS) on the then-new 100 L Macro. and it's good business to play up all the new technology in whatever item you're selling, it's been demonstrated that consumers are (wrongly) easily impressed by the quantity, not quality, of features and specifications. between two identical items put up for sale, consumers will more often choose the one that has a longer specification list posted.
I'm fairly sure if BSI on large sensors were being employed by Canon on the 1DX, they would be talking about it (especially what with all the white papers they've posted so far). I don't think this will stop people from purchasing the 1DX any more than the future 5DIII has stopped people from purchasing the real, current 5DII.