They are being attacked by the great Satan, and Israel... Decades/centuries of hatred aren't wiped away because you dislike the bosses.
There is a reason dictatorships use war to shore-up support when they are weak. There was potential that cutting off the head would topple the regime, and it didn't happen. That doesn't mean that when the inevitable peace happens the public will still tolerate them. As
@KevinB and others have pointed out, the problems that existed before haven't magically gone away because the economy has been shut down, and all their stuff has been blown-up.
Is Iran making more than they did before the war? No. Is their economy functioning? Not really... Again, all the problem s they had before are still there, and when the unity caused by an outside enemy fades, things aren't going to be rosy for leadership.
The IRGC is in power, until someone inside decides they can do better for themself by changing things up, or the people get tired of their bootheel. Whether that's tomorrow, or two years from now, the current war is weakening the system currently in place.