I don’t think the government will be removed by a majority vote in the IRGC and replaced by sane muslims.
There have been a number of surveys on the current religious makeup of Iran. Those using telephone and face-to-face survey modes show a very high percentage of Iranian identifying as Muslim—99.98% in the official 2011 Iranian government census, whose numbers were used by the CIA World Factbook, and 96.6% in the World Values Survey in 2020. The CIA World Factbook estimated that in 2020 98.5% of the population adhered to Islam. Online social media-based surveys conducted by GAMAAN, which use chain referrals to self-select participants, reported that Shia Muslims constituted 32.2% of Iranians in 2020, 56% in February 2022, 37.5% in December 2022, and 37.9% in July 2023. The U.S. News & World Report placed Iran 3rd on the ranking of the most religious nations in 2024.