They could be gassed in a day and ended you are talking about a insurgency civil war as signficiant..There is no reason commiting further genocide on them than they are already claiming has been commited. You lost to a Sadam who had 5 times less population..
Just one Country in the Persian gulf can logistically fuk up all of Irans infras in the country like Qatar it has the logistical means to do that. Forget about adding everyone else on top..
Algeria itself in 1v1 could fuk Iran totally. Forget about adding 1m Peninsula shield forces including Egypt, Jordan, Sudan etc etc..
They could invade Iran at will whenever they feel like it is time to go...
Iran is a paper tiger and always has been historically we know that inside and outside.. The same Arabs came out of the desert and took over all of Iran and they could do it again without breaking a sweat and it would be much easier this time than it was last time