"Everything played itself out. There was no way that the spirit of the revolution would have fizzled out inside Iran nor the eagerness of the people for revolutionary change could have been dampened," said Haleh Esfandiari director of the Woodrow Wilson Middle East Program in Washington, DC.
What Iran did was give a lot of inspiration to the people on the streets for three decades before the Arab Spring started… because the Islamic Republic stood up to the United States and stood up to Israel, and doesn't shy away from expressing its views, over the years on Saudi Arabia, on Jordan, on the Persian Gulf countries.
"But then there was Saddam Hussein's invasion of Iran in 1980, which, ironically, strengthened the revolution and fed Iranians the determination to carry the revolution outside Iran's borders," said Esfandiari.
With time, the Islamic Republic's influence reached far and wide.
"Iran's creation of Hezbollah in Lebanon altered Lebanese politics forever, and opened a second front against Israeli ambitions, which had not been imagined," said New-York-based journalist Hooman Majd.
"So undoubtedly Iran has gained influence and strength, and as a nation with an ideology independent of East and West, has to now be considered in any Middle Eastern issues. That in itself is a change in global geopolitics, where before the fall of communism you had an East-versus-West scenario everywhere, including the Middle East, with players lining up on either side, and now you have Iran in the mix."
Had the revolution not taken place, "We'd be looking at a different Middle East," said Gary Sick, former National Security Council analyst on Iran and a professor at Columbia University's School of International and Public Affairs.
"Basically, the Iranian revolution was an enormous shock to the system, especially in the Persian Gulf… The fact that you had this power coming in with really revolutionary objectives, including an objective to try and overthrow the monarchies - they don't talk about that any more - that scared them to death," said Sick.
That fear set in motion conflicts and alliances that, 35 years later, still shape the region.
For example, Iraq's attack on Iran not only rallied the population around Khomeini, but also served to galvanise a network of those who opposed the Islamic Republic.
"And the Arab world's support of Saddam all the way through, and Saddam's attack, and the spread of that war through the Persian Gulf, and the oil lines in particular, gradually drew the United States into the Middle East," added Sick.
And this too had its consequences: It invited the US as a major military force into the region.
New geopolitical chessboard
Even to those who weren't tracking regional changes, the hostage crisis - where revolutionaries took 52 Americans hostage for 444 days in the barricaded US embassy in Tehran - signalled the start of major hostilities between the US, its allies, and Iran, resulting in, among other things, decades of sanctions.
"It is fair to say that Washington was beginning to get worried about the anti-status-quo messages of the Iranian revolution even before the hostages were taken, but the hostage crisis was a game-changer," said Boroujerdi.
The sanctions that for decades jeopardised Iran's economy and wreaked havoc with the world's oil markets can be traced to the hostage crisis.
"The American political class has never recovered from the shock and humiliation of the hostage crisis. It cast Iran as the face of evil in many American hearts," said journalist Stephen Kinzer, author of several books on US-Middle East relations.
"This anger is the main reason why the US has been so unrelentingly hostile to Iran over three decades," said Kinzer.
Beyond the anger and humiliation, Majd said one of the seismic results of the Iranian revolution was that it forced the US into building a military presence in the region.
"Up until the Iranian revolution, the United States had been very reluctant, under [President] Jimmy Carter, to create a base in the Middle East... The revolution changed their calculus," said Majd.
The US had almost no military presence in the Gulf area until about 1986. Now it has a base in almost every country in the region.
"[Increased US military presence] started with the Iran-Iraq war, and stepped up when Saddam Hussein made the incredibly stupid mistake to invade Kuwait in 1989, and that drew the United States in a major way and we never stopped maintaining our presence there," said Sick.
The US troops he drew into the region, said Sick, ultimately played a role when the US decided to invade Iraq in 2003.
"The irony, in turn, is that the United States invasion of Iraq and Afghanistan eliminated Iran's two biggest rivals in the region [the Taliban and Saddam Hussein] and left Iran as the most important player, which is why the Arabs are so scared. And yeah, all that started with the revolution."
Arab Spring legacy?
So far, there is no indication that any of the uprisings in the Arab countries will follow the Iranian model, even though, as Boroujerdi puts its, "The lasting impact of the Iranian revolution was the empowerment of Islamic groups which could now begin to envision themselves as rulers, rather than merely the opposition."
Esfandiari rejects any assertion that Iran has become a model for other revolutions in the region.
"What Iran did was give a lot of inspiration to the people on the streets for three decades before the Arab Spring started… because the Islamic Republic stood up to the United States and stood up to Israel, and doesn't shy away from expressing its views, over the years, on Saudi Arabia, on Jordan, on the Persian Gulf countries," she told Al Jazeera.
But things changed after the Iranian government's harsh crackdowns on the opposition Green Movement in wake of the disputed 2009 presidential elections , which saw Mahmoud Ahmadinejad take his second term in office.
"I think after 2009, this changed among the people. I think the people in the region who watched the brutal suppression on the streets of Iran were taken aback and changed their minds.
"After that, nobody wanted to imitate Iran."
From revolution to 'evolution'
| The Islamic Revolution's late founder Ayatollah Ruhollah Khomeini, still looms large in the country's psyche [AFP]
Looking at the ever-shifting sands in Iran, it is only logical to wonder if the constant struggle to define the Islamic Republic means what started decades ago is still rolling towards either a more moderate or conservative state.
"No, I don't believe this revolution is yet complete. The formation of a theocracy was both novel and anachronistic, and it will take more time for its ramifications to play themselves out," said Boroujerdi.
"The revolution has upgraded the level of political sophistication of the citizenry and it has given birth to new institutions that are still in their early stages. Iranian politics has become 'real' as a result of the revolution and this permanency has become the new 'normal', which we need to get used to," he added.
Sick said Iran's revolution is unusual in that it has gone from a revolution to an evolution - "that is, from ultra-radical positions that they took in the first two, three or four years to a much more moderate, pragmatic position. With this recent agreement on the nuclear issue... this is their effort to become a normal country that actually participates in the world", said Sick.
"But look... revolutions take a long time. They change things, they throw things up in the air - and then things begin to settle and you never know how it's going to settle and how things will work themselves out."
Follow D. Parvaz on Twitter: @dparvaz