My own distinction between ML and AI (which I agree with the article that marketing buzzheads do not care about) is that one is a set of optimization techniques

My own distinction between ML and AI (which I agree with the article that marketing buzzheads do not care about) is that one is a set of optimization techniques not necessarily involving an agent, and the other involves an agent, who needs to make (intelligent) decisions. The decisions themselves may rely on said ML-based optimization techniques, or they might not. Similarly, optimization techniques may employ an agent-based approach, but equally they may not.