See my post above re: manipulation of the region by outside powers. It was going to be controlled by the west, or by communists. No other option.
So Iran was a pawn caught up in the conflict of superpowers. And yet, Iran survived the coup and became more modern and culturally westernized under the pro-western Shah. That was finally the point of it, to bring it under western influence. Over time monarchical rule softened, the Shah did not have absolute power but shared some of his power with a parliament. Things were going the right way, towards a parliamentary monarchy but as an ally of the west. Had they been left to fall under communist control, I think the outcome would have been far worse.
Then, a third player stepped in. What happened next was the true catastrophe for Iran, NOT the coup of 1953.