Ultimately the only thing that holds true about AI is Tesler's Theorem:
Artificial intelligence is whatever hasn't been done yet
Machine Learning is only still artificial intelligence because we haven't figured it out. Ultimately ML is just fancy control theory. Once the field is sufficiently explored, it will slowly stop being AI and will start being treated as a subset of control theory instead. I doubt it'll happen any time soon but it'll happen eventually.
This is in the same way that algorithms, combinatorics, and graph theory when applied were seen as AI anywhere from 70 years ago to as little as ~25 years ago. Those fields' applications to unsolved computing problems (that humans could do) was what made them AI and once we solved those problems, they (and the techniques used) stopped being AI.