We can't just change our strategy to "nvrmd: kill 'em all" and think we'll have any allies after this. Iran would once again not just attack us, but practically every country near it, causing even more causalities and infrastructure damage.
And this doesn't get into the problem that this would eventually require a land invasion, which would be impossible. We couldn't even get an actual war ship close to Iran.
There is a "Sunk Cost Fallacy" that someone in our Administration should listen to. Times up with this complete disaster.