I would dispute the depletion of expensive munitions, but I still believe that is largely irrelevant next to political exhaustion.
I do not think most Americans would care to defend Taiwan, even against the China boogeyman. The practical realities of losing Chinese goods would be a devastating reality few are prepared to face.
The reality of losing TSMC is no joke either. I remember Covid times when many G20 leaders went to Taiwan begging for some chips so that they could keep exporting cars and other things that need computer chips.
I agree, political exhaustion is the real constraint.
I personally would not be willing to do anything to defend Taiwan from China. But then again, I don't support any of the wars we fought in the middle east, either.
I think people are pointing out how little it actually takes to wage this war against Iran and that there are basically zero costs to the USA to do so. A classic "political exhaustion" requires some degree of meaningful hardship on the USA and a slight gas price increase just isn't enough.