It will not fall as long as only it has the guns, don't kid yourself. Unlike the Shah's forces, these people fight for Allah and Islam. As Khomeini said, if the only way for Iran to preserve Islam is for the whole country to burn, then let it burn. This is the mentality of the mullahs and RG around Khamenei. Either die, give up, arm yourselves, or ask for US help. These are your only options.