No Gaither apologist here. In fact quite the opposite. I like the question you pose: if Gaither's foot/back/weight loss injuries were not gambits (which I belive they were at least in part), then Oher wins [the competition for LT that never happened] by default, not fiat of Harbs. All along I didn't like the appearance that Gaither seemed to not believe he had to work for his football career (at Maryland or in the NFL). Part of any job is following directives of your superiors. If one looks for it, one can see a lot of opposition defiance behavior from Mr. Gaither and/or a lack of interpersonal skills or maturity to navigate the complex professional relationships which exist not only in big time football but every adult work role. Maybe Harbs , etc. said "Let's give him another challenge and see how he responds." If so that backfired and convinced the Harbaugh-era Ravens' brain trust that Gaither was no longer a priority.
Hope the dude makes good on his most recent opportunity, if only so we can shut up about him! He was the right guy in the right place for SD late last season (expectations couldn't have been lower for their OL at the time). Perhaps the media market is more SoCal mellow out there (I know the medical marijuana scene will suit his [oft rumored] "holistic approach" to conditioning), and he's far away from the Univ of Md. chapter of his story that played so poorly in the Ravens' home markets. He's gone away, now can we just make him go away?