What’s the demographic of these pockets why are they unlikely to unite? Are they just too different?
Iran's been hit by waves of protests going back 15-20 years now, and they've been increasing in numbers & intensity over time (as many as 1,500 people were killed each time in the biggest of these, the 2020-21 and 2022-23 protests). There's genuine, non-astroturfed discontent with the Mullahs (if it were a color revolution, it would've been snuffed out long ago, like in 2009) - best way I've heard it put was by a politics prof a decade ago who explained it as 'Saudi Arabia is a nation of Islamist fanatics ruled by a secular-minded elite, Iran is a secular-minded nation ruled by Islamist fanatics, and much of the internal troubles in both countries can be traced back to this dichotomy'. (The House of Saud is infamous for both their historical friendliness to Western interests and being filthy degenerates behind closed doors, to explain the first half - part of OBL's sneeding in the leadup to 9/11 was that the Saudis hosted American bases & would rather take American help vs. Saddam in the Gulf War rather than call for faithful jihadis - but I digress.) The ruling theocracy famously were not the dominant faction in the Iranian Revolution which overthrew the Shah originally and did not actually have majority support at the time, Khomeini had to outmaneuver the commies and the liberals to seize control in the end (there's the future of all the 'Queers 4 Palestine' types who think they can be friends with Islamists, if they were to ever come anywhere near real power).
The Mullahs aren't terribly fond of the Iranian identity and history, which had its glory days in the pre-Islamic period; the Achaemenids and Sassanids blow all of the Islamic Persian empires, from the Safavids to the Pahlavis, out of the water in terms of size, relative power & relevance for their time period, but as far as Khomenei, Khamenei and those who follow them are concerned, the day the Arabs destroyed the Sassanid Empire and subjugated Iran to Islam (it took until the
Safavids - a dynasty of originally Azeri-Kurdish origin - 900 years later for Persia proper to regain its status as the core of an imperial civilization, and 1100 years for an actually ethnically Iranic dynasty to rule Iran again with the
Zands) was the real greatest day in Persian history, as can be expected of hardcore Islamists. Suffice to say a lot of Iranians disagree, and they also don't much care for the strict religious laws of the Mullahs in general, hence why if you look at videos of daily life in modern Tehran you can find people still flouting rules like the mandatory hijab (and that's just in daily life, outside of a protest/riot).
However! These protests & riots, while increasingly huge, are also hugely disorganized. There's basically
no known domestic anti-regime leaders or organized movements of note, hence why they keep getting crushed over and over despite getting tens or even hundreds of thousands of angry people into the streets each time. (This is also why I doubt these are 'color revolutions', those tend to be better planned & organized by CIA/'democratic' NGO/whatever stage managers.) Pretty much the only Iranian opposition leader whose name is even slightly well known is Reza Pahlavi, the exiled Crown Prince and heir of the last Shah. However he hasn't been back to Iran since the Islamic Revolution in 1979, for obvious reasons. There are still monarchists in Iran (they managed to get like 20,000 people in the streets during the Cyrus the Great protest back in 2016) but it's very difficult to gauge how much support they actually have (it's not like the Mullahs would allow pollsters to ask such questions), and it's not terribly likely that they constitute a majority of the opposition
in Iran. Out of Iran it's a different story, Pahlavi is massively popular with the Iranian diaspora (anecdotally I went to high school with an Iranian girl who was a fervent Pahlavi partisan like the rest of her family, and an Iranian driving instructor I once had was also a fan) but, you know, those are exiles living outside of Iran or their descendants, so not super relevant to the prospect of a rising inside Iran.
Also, Iran's demographics aren't as much of a clusterfuck as some other Mideastern countries, but there are still some pretty serious ethnic & religious divides there. This is a map of the major ethnic groups inside the country:
The problem groups atm are the Kurds, the Balochs and the Azeris. There are armed Kurdish & Baloch secessionist groups which have been actively fighting against the Iranian government for a long time already, the Kurds claim to want autonomy instead of independence, the Balochs want their own country period and are also fighting Pakistan for the same reason. As for the Azeris, Azerbaijan has a historical claim to NW Iran and as the Nagorno-Karabakh Wars & ethnic cleansing of Armenians there after the final Azeri victory in 2020 show, they take that shit extremely seriously. Iran is also friendly to Armenia while Azerbaijan is friendly to Israel, so there's plenty of room for mutual seething there. Balochs to my understanding are pretty hardcore Sunni Muslims as well, not too different from the durkadurkas in Pakistan and elsewhere, while Kurds and Azeris tend to be secular/irreligious nationalists. (
Azeris especially, the Soviets beat the durkadurka-ness out of them so they substituted Islamist zeal with ultranationalist zeal instead, they will literally murder their historical enemies - in their case, Armenians - while on a NATO training mission where they should theoretically have been on their best behavior, only to be celebrated as a national hero, and their gov't will then blatantly lie & break every rule they can to bring them home to a hero's welcome.) The Soviets have previously
sponsored rebellions against central Iranian gov'ts in that region in the northwestern region multiple times in the past, it's been restive for a long time.
Tl;dr Iran is both more and less stable than it seems. You probably are not going to see a massive revolution toppling the Mullahs overnight, rolling out the red carpet for the Pahlavis, forming a constitutional convention, etc. any time soon until and unless the IAF/USAF severely degrade the Mullahs' security apparatus (not just the IRGC but also the police and paramilitary Basij), which they haven't even really gotten around to starting yet (the Israelis have been mostly focused on blowing up nuclear sites & scientists and the IRGC only, though I heard they bombed the police HQ more recently). However if shit gets real and TPTB go all in on regime change, the lack of organization among the Iranian opposition on the ground, mixed with the existing ethnic insurgencies and potential Azeri irredentism, can cause things to spiral well out of anyone's control very quickly.