It's likely that Iran will come out a loser, but also likely that the USA will lose too -- winning a war is more than making the other side lose which is what keeps getting the USA on the hook for multi-trillion dollar, decades long wars. Removing unwanted leadership is only effective if there's a viable plan to replace that leadership.

Yet the chronic 'loser' US is somehow the superpower hegemon

And the USA is even losing its hegemony with the Iran war that's causing global pain without global consensus that it was neccessary, but the real loser in the USA is the American taxpayer who gives up domestic social benefits to fund these wars.