I hope you are right that most Iranians are pro American. I hope they can come to power but I tend to doubt they mullahs can be overthrown. For all the Russians have done to them it will be us who turns their country into a field of glass when they nuke us. It’s not “if” it’s “when”.
I wouldn't say most of the entire population. But most of the middle/upper class. These are the folks demonstrating.
The poor slum dwellers are religious/superstitious and susceptible to regime propaganda. Not all of course... but at a vastly higher rate.
The problem is that for half a century the educated/upper class were calling the shots, and thus Iran was pro-American. After 1979 the mullahs with their poor slummy base have taken over and repress the old elites.
I have also my doubt over the success of a new anti-Mullah Revolution... a Revolution needs arms and funding. The islamists had this 1979. Today there are no gun-rights and no comparable organization. They also have no outside help (thanks Obama!)... very different to the situation then with Carter and the KGB pulling strings to topple the Shah.
BTW I think that Israel needs to destroy the nuke facilities ASAP. It's the only way to prevent a worse scenario for everyone involved.