You're right. There are no guarantees. No guarantee that if they let Strasburg continue that they'll even win a pennant much less the whole shebang. I will give you one guarantee, though:
If they hadn't gone down this road, didn't implement an early shut down and let Strasburg pitch AND his elbow blew again or his shoulder got toasted, the firestorm would be unprecedented. And I guarantee you that a majority of the experts and pundits who've sounded off against the shut down would be leading the lynch mob.