I thought this as well, or it could precieved to be an act of Jihad or a number of different reasons. The truth of the matter is we will never know with 100% certainty when the government is telling the truth.
Yes, there are actually several believable reasons that could fit.
*If he were alive though he'd make it known that the US failed in its attempts to have him killed. His personality wouldn't let him live a quiet life.
He may not want to press his luck, and he may also be working with Americans.
But ftr, there are reports to say he has made recordings announcing he's alive.
As you say, though, we'll probably never know. My only point is that certain Americans (and others) will lie like it's nothing. So watching TV and assuming it is truth is a dumb habit.