I think the 30% of Shia Muslim statistic more closely aligns with overseas Iranians. According to a survey, roughly 30% of American-Iranians identify as Muslim (PAAIA).

Mosque attendance in Iran is low. Some might argue that this is an indication that a considerably lower percentage of the population is actually Muslim. However, mosque attendance in Iran has been low for a long time. In 2006, less than 30% attended mosques weekly (Researchgate).

There are at least 6000 inactive mosques (Iranwire). Other sources are claiming as many as 50,000 are inactive/closed.

It looks like Iranians are moving towards more secular beliefs (Iran Academia Journals). It seems like a slow shift. I doubt there is enough urgency or anger to spark a revolution anytime soon. The next year or so will answer that question.