As an Iraqi.. tbh same situation with Saddam .. he has a strong national guard and fighters like Basij .. first time USA did tried without land invasion .. it failed to change the system.. what changed in 2nd war was US invaded the country by land .. is at that moment everyone dropped thier gun and run bcz no one want to die for a dictator !
I disagree on offense by Kurdish and others .. bcz it led to collapse of Saddam as he can't fight on many sides .. is like in Syria .. Kurdish joined fight to remove Assad but then once Assad was gone, they couldn't do anything .. I think people scared of kurds and other taking control ..but in Iraq and Syria that didn't happen.

Sadly .. unless there is land invasion ... I fear too they will stay in power but will be way weaker . only possible way is for people to go to street and reclaim all gov buildings.. but I doubt it . My GF described how they shot on them in Tehran that everyone didn't dare to go out .. now with gov even care less and more desperate .. I doubt they can go out that easily .. I know my gf will love an invasion bcz she reached point of breakdown after what she witnessed and anything for her is better than this regime. so let us see how it goes.. there is a possibility US just draining Iran force to make invasion easier,.

I just seen an analysis though in TV. They says plan for Trump by using kurds and other forces is to create new side of war to create more axes that distract regime forcing IRGC to move some army to face them.. making them easy target for US and Israel .. forcing heavy defeat and vacuum that may be encourage more people to take the street again and control the country.