You're making an assumption which is not necessarily supported by the facts in evidence--that Palin is "exiting stage left."
I read her full statement on her web site, and it's clear to me that she's strategically redeploying, and has no intent to abandon the battlefield. (Note the General MacArthur quote at the end of the statement.)
Now, this may be a brilliant move or it may be a terrible mistake. Or it might be somewhere in between.
Time will tell.
I agree with you entirely. She’s running. Why else would she mention the whole fish swimming upstream bit and all. Quitting now gives her a chance to bone up on world politics, take MJ off the front page, and gives Alaska back to Alaskans.