I think the unstated point is that McCain’s health is not good and the man looks like he’s on death’s door. There’s probably a chance that he would not survive his first term in office because of his deteriorating health, and that his VP choice is absolutely critical for the future direction of both the GOP and the country.
That’s a might big if. FDR lasted for 3 terms; I don’t think McCain is quite as feeble as people wold like to imagine.