The Islamic Revolution happened because the Shah sucked in major ways, the religious extremists were just able to latch onto the popular discontent and say “The Shah is as evil as he is because he has fallen out of step with Islam and instead is a puppet of the Christian West” which is a statement I disagree with, because I don’t think religion had anything to do with why the Shah sucked. But he WAS 100% a puppet of the West selling out his own people for Western interests, that part was true.
The Islamic Revolution in Iran is a complicated case, because the people absolutely had legitimate reason to overthrow the Shah, but I absolutely agree that the Ayatollah is only a marginal improvement. Middle Eastern revolutions often go that way, where yeah clearly the pre-Revolutionary leader was unpopular and had to go, but the Revolutionary leadership isn’t really that much better. Iran’s revolutionaries at least achieved stability though, they may not be righteous but they were effective.