If by swan song, will he be out in the next 12 months? I doubt it.
If by swan song, you mean his last "championship shots". I think so.
Big Show doesn't make sense carrying titles anymore (in fact, it could be argued that he hasn't for a few years) simply because he can no longer be a candidate for "Face of the Company". This is due to his age, the character he has created, and the basic fact that there are other, younger guys who fit the bill so much better (Bryan, Punk, Orton, Rhodes, Sandow). But, I do think he'll be around for a few more years, just not as active in the ring. He's more into the "cutting back on matches to prolong his career" stage of his career.
wk