Iran has significant Kurdish, Azeri, Baluchi and Arab minorities, Persians form cca 2/3 of the population.

With the US & Israel supporting the minorities (most likely offering them independence), in the hope of toppling the regime, and bombing mostly Persians, the most likely outcome (assuming they are actually able to force regime change, which is far from guaranteed) is fragmentation and general lawlessness.

Note that whoever inherits the regime would have to deal with wholesale destruction of the country, traumatized population and hate for those who bombed them and killed their relatives and children. Slavishly obeying the new foreign overlords will not be very popular. Have we not learned anything from Iraq and Afghanistan? How can you still believe the fairy tales of welcoming the liberators?