I agree with all this, but I'll add a caveat from personal experience:

A harsh Sunni-Shia civil war broke out during the years I got sent to Iraq (the civil war lasted from approximately early '06 until early '08). The sectarian violence that ensued was far worse for Iraqi civilians than what AQI was doing to the Iraqi government forces and US forces combined. The Sunni/Shia militias went after the other side's civilians almost exclusively (they also went after US troops and the Iraqi army/police, but they primarily went after their domestic opponents). There were something like 160,000+ civilians that died during the Iraq war, and the bulk of them were during this sectarian violence that occurred between Sunni and Shia for about 2 years--a prelude to what would happen later under ISIS after the Syrian civil war gave it room to grow and spill over the border in 2013. The thing is, sometime around late '07/early '08, the Sunni populace of Iraq turned on AQI. They had enough of their people dying at the hands of Shia militias and Iraqi/US forces (sometimes the Shia militias *were* the Iraqi police btw), and they turned on AQI and stopped supporting them. I sometimes wonder if something like this could happen between the Palestinian populace and Hamas, and if it could, perhaps this is the kind of thing that would turn the conflict and give way to something like a foreseeable end state where it's not Palestinian militants being in charge of the populace and allow real negotiations on a 2-state solution taking place. I just don't know how easy it would be for us to get there considering how much popular support Hamas (and Fatah in the WB) enjoy from the Palestinian populace. That said, I would have thought the same in 2006 regarding Sunni public support for AQI, so who knows what is possible in the future.