Kinda just rambling thoughts, but…
I believe the focus is a bottom to top approach. An attempt to irradicate these groups, not just take key figure heads. Does it really matter if figureheads or even key players are still moving about? Would it really matter if something happens to them? Is it more important to fully complete the mission or just take revenge/satisfaction from a few individuals?
There's also the PR piece. It's been said much of the world is misled by what is portrayed as true. How would it really look for it to come out Hillary, Obama, etc were wearing trackers or had been arrested. Imagine the outrage if Hillary was just randomly taken on US soil. I doubt justification for protests, armed groups, splitting the country is what q team wants. In this light, maybe some players are untouchable at the moment and both sides know it.
People post things about gitmo, hangings, etc but they would just make people feel good. A big pat on the back. Unlikely they would even help. Who's the man behind the man behind the man behind the throne?