And then if you have people flying the planes, you have to deal with people mostly _but not always_ doing the right thing. So now you build out a plan and have to deal with consequences of that.
So at the end of the day you're still looking at funneling humans into a thing. At worst you could consider ATC as "customer support", there to press buttons on machines to actually handle a bunch of logistics because the pilots need to figure things out.
On top of all of this, airports are trying to get through a lot of flights quickly. So people can make snap judgements about whether planes can or cannot advance, what they should do, etc. No matter how well your plan is, the instant a pilot mishears something it's over.
If we can figure out self-driving cars, maybe we can talk about replacing pilots with AIs. But in the meantime there's somebody not following the plan often enough.
This does lead to an interesting question for me, though: what is the biggest "human movement" system that is actually entirely hands-off logistics? I would imagine that postal service companies are doing a lot but every major person moving operation seems pretty hands-on from the outside.
