Would a full scale ground invasion of Iran be successful in removing the regime?! Logically you would capture all their main bases, missile production etc, the IRGC would end up becoming terrorists, you would however be able to build a new Iranian government and a new Iranian military who would be able to fight back. Difficult to see the regime ever taking power again though there would likely be ongoing terrorism.
Such an invasion is going to be very costly in terms of lives and money. Could Gulf Arab states be persuaded to take part?
Going forward if the regime is left in power it will continue to be a problem in the region and likely feel emboldened as it has survived, likely eventually getting nukes. Either the west backs down and leaves the regime in place as it is too tough to remove or go for total regime change. The regime in Tehran always seemed like way more of a threat to me than Gaddafi, Assad or even Saddam yet all those were removed while the most dangerous regime was left alone. Iranian friends have actually asked me why it is their regime was left alone and free to murder them while the west would get involved just about everywhere else.