Cyanogen, the initial author, was hired by Samsung some time ago. But CM is still a volunteer project, the developers don't get monetary compensation for their work, so there's nothing to buy out.
They of course could keep on working on CM in general, and do contracting for other people as well, but at least your phone would have CM support out of the box.
I imagine the CM people could organize a bit to facilitate such contracting, but I suspect the reason this hasn't already been happening is that there just isn't really any demand from the manufacturers. I can't really say I know anything about the industry at all though, so I might just be talking crap.