I think you’re wrong in this assessment.
Terrorists can never win a stand-up fight with a modern military on a battlefield, or even in an urban house-to-house environment.
But terrorists could bring a nation to it’s knees by attacking infrastructure instead of blowing up cafe’s and sandwich shops to kill a few dozen people. Blow up oil and gas pipelines, take down transmission lines, blow out dams, levees, hydro installations, etc.
Pretty soon, the mass of the population is in the dark, perhaps freezing, (or baking) and they’re hungry. The government has to turn resources inwards to deal with infrastructure failures instead of chasing the terrorists, or the government falls as people riot. There’s a Chinese restaurant fortune cookie that says “An empty stomach makes a poor political advisor.” That’s very true in this case.
A small groups of engineers turned terrorists could bring the US to her knees in about four weeks.
In the middle east, a smaller group of engineers could bring the region to it’s knees in about the same amount of time. They’re overly dependent on “bigger, fewer” pieces of infrastructure. Lots of that infrastructure runs through areas of desert with no security or supervision. Easy, easy targets.
Someone is getting smart here. A few more IQ points and some follow through and there’s going to be Real Big Problems.
And I think you well may be correct in your assessment. If your(not yours personally, but the adversary) whole desire is to create chaos, mass casualty, etc. then swoop into control in the aftermath, your proposed scenario works well. If radical islamists want to bring Egypt and others to their knees, starve or kill off 2/3 or more of the population and rule the remnant, then yes that is a strategy.
If you want to take over and retain the bulk of the wealth and infrastructure, maybe not so much.
In any anihilistic approach, there is no room for error. Failure to completely eradicate your opponents sows the seed of your own destruction. Push come to shove, Israel can drop a half-dozen retaliatory nukes and surround themselves in a sea of glass.
Faced with their own extinction, they are prepared to do this. The US is not so determined, I suspect, so the ugly face-to-face, field-by-field scenario may well play out here.