You probably got the "he seems smart, but I would expect someone with this much experience to gave progressed farther in his career, no hire because no trajectory , we can't hire someone with 15 years experience at the '7 years of experience' level he interviewed at". For people who are solid contributors and not "management material", this looks a lot like ageism, but technically maybe isn't.

Now, why they want everyone at a 50K engineer company to be management material...seems ill advised.