The Revolution occured because the old regime was even worse than today's one, just because a few of the old elite migrated to the West and started pouring propoganda about how great the Shah was doesn't mean that people of Iran feel the same way.
The non-Persians of Iran sure were greatfull that the Shah was booted out thats for sure, Ayatollah Shariatmadari was a big reason for the revolution occuring and if he had got his way Iran would have been in a much better position today, he didnt want religion to mix with pollitics and wanted to give rights to all people of Iran. Sadly he was arrested for no good reason and stripped of his title and perished