By regional powers you mean Saudis, Bahrain, Qatar and the UAE with no constitution or ballot boxes?
All of those countries have constitutions. More importantly all of those countries are
lightyears ahead of Iran in terms of HDI index, infrastructure, law and order, economy, connectivity with the outside world, living standards, prosperity, support for their rulers etc.
Arabs, in case you missed it, had a so-called "Arab Spring" 10 years ago that impacted almost every Arab country. Arabs have a history of removing leaders that they don't like.
Why should people of the GCC be any different in this regard? They are richer and more connected to the outside world (more students abroad per capita than anyone in the region by far) and could easily protest/make revolutions if they were genuinely unsatisfied with their lives and leaders.
But they don't. You know why? Because they live better than 99% of all the world's population. Which is also why GCC is one of the main migrant/immigrant hubs on the entire planet, including attracting some of the largest Iranian diaspora in the world.
And locals in the GCC have their own ancient systems where the people directly consult/talk with their leaders through Majlis, elders, people of power etc. The idea that Western democracy is the only solution is ridiculous. Compare "dictatorship" China with "democracy" India.
Ironically Kuwait, which has its own democratically elected parliament, democratically elected politicians etc., is the most ineffective and worst performing GCC nation. Food for thought.
And please don't start this joke of Iran being a democracy because Iranians can vote every 4 years on 2-3 state-appointed candidates. I would take it seriously if some Dane or Scandinavian person was preaching about their genuinely democratic systems. Which were not developed overnight but mostly in a bloody fashion.
Not to mention that the real ruler of Iran (Khamenei - head of state too) has been ruling the country for almost 40 years.
Everything has its time, whenever the need for a Western-style democracy occurs in the GCC, it will eventually be implemented if that is what the majority will want. You cannot oppress the will of the nation/people forever.
But as of now vast majority of locals in the GCC support their leaders and systems, they cannot afford to do anything else considering how well they live compared to everyone else in the region.
These 5000 people (out of 86 million Iranian population) are the biggest threat that one can imagine, Iranian leaders know this is the end...
Seems that Iran is the only country where protests every 1-2 years with 100's of casualties is seen as a "normal" occurrence. I wonder why such protests never occur in for example GCC states? Can you explain?