I can't imagine why Texas Instruments' lack of support would be relevant in any way unless the phone vendor seriously lacked foresight. Most hardware manufacturers won't ship a closed binary blob that they don't build themselves. They may not be able to make the sources available, and it may be guarded under piles of NDAs so tall that the falling tower of paper would kill anyone who tried to leak it, but that doesn't mean they don't have the sources. I can't imagine that even Samsung would put themselves in such a vulnerable position.
Then again, if Samsung really doesn't care much about long-term support, maybe they would.