Well, there was pressure, until the Obama administration released $50 billion back to the regime https://www.factcheck.org/2019/03/obama-didnt-give-iran-150-...

And economic pressure means nothing to a theocracy that governs over a poor population. That is in fact their bread and butter.

Look no further than Afghanistan to see how resilient they can be. They even withstood decades of occupation.

Hard power alone wouldn't have worked and who knows whether soft power could have worked either since there were so many saboteurs both internal and external like Saudis/Israeli lobbies killing the project in its infancy.

The Islamic Republic is nothing like the Taliban. The Iranian population, especially around 10 years ago, was by no means “poor.” Iran has rich natural resources, very well-educated people (in STEM), and one of the oldest extant cultures of the world.

Eh, that reduced it but definitely didn’t release the pressure. Trump turned the screws down pretty tight in quick order too.