But context is important. "Low-hanging fruit" doesn't mean the solution is "easy" in a vacuum, it just means this specific aspect is the easiest and/or most obvious place to start attacking a problem.

Or to stick with the language of the analogy, every fruit tree has some fruit that is lower than the others. That doesn't mean all "low-hanging fruit" is within arm's reach of the ground, some fruit just doesn't require as big of a ladder as other fruit.

This comment isn't a judgment of this specific case. I don't know enough about ATC to have any confidence in my opinion on the viability of replacing humans with software.