Problem is that the RNC does not work like that, and its chairman is not the final decision maker, as in the DNC. The RNC chairman answers to a board comprised of all the GOP bigshots, who can veto and diminish the chairman at will before finally casting him or her off when convenient. The only reason that Steele has survived so long is because of his ethnicity and the fear of the MSM's inevitable backlash, stoked by the Rats.
Palin would do very poorly as RNC chairwoman simply because she would not be the party's true shot-caller.
Those same GOP bigshots won’t let her be the nominee either.