The thing about machine learning (ML) that worries me is that "knowledge" acquired in ML is hidden: we usually can't explain the criteria or methods used by the machine to provide an answer when we ask it a question.
Edit: It's as if we asked an expert financial analyst for advice and he/she replied, "Invest in X"; then when we asked "Why?", the analyst answered, "Because I have a feeling that's the right thing for you to do." It makes us dependent on the analyst. end edit
Surely there are some researchers trying to find ways for ML systems to encapsulate and refine their "knowledge" into a form that can then be taught to a human or encoded into a much simpler machine. Who, if any, are working on that?