Don't overlook the "the people of this foreign land are yearning to be free of their current rulers, and just need a little help from their neighborly U.S. armed forces" trope. I think there are plenty of people who actually believe it.
The US (well Israel) saw this as the stars aligning. Trump even called on Iranians early in the engagement to seize the opportunity.
But the ground swell didn't happen, and the US got played. Trump rolled a critical fail.
How it could be a surprise more riots didn't happen?
It's almost like you can't paint an entire country with one brush?
A.) Would you be happy if the government changed? (85% approval)
B.) Are you willing to potentially sacrifice your life and the lives of your sons to change the government? (3% approval)
No one in Iran wants their children bombed for US to "free them". US and Israel don't care about Iran.
They just want to destroy our country and take our wealth. Like they have been doing all over the world.
Source: Iranian who doesn't support the Islamic Republic, but have some family members who do.
We can resolve our internal issues with discourse (and sometimes violence if it comes to it).