You're absolutely right. As long as he keeps his mouth shut, he's "that other guy who isn't Bush." And that gives him the votes of the even vaguely grumpy.
But he can't stay invisible forever, of course. And once people get a good look at him, he's toast.
That's right. It will be his name on the ballot. If a voter can't form a picture of a candidate in his mind he won't vote for him. The only numbers that count are the numbers on election day.