I was trying to avoid sounding condescending and privileged, but I think you’re right. My first ten years were spent in very niche programming (Lotus Notes) without any mentors. It nearly sank my career and ultimately took me about another five years to rebrand myself as a full stack Java/JavaScript developer and now I’m strictly back-end/leadership. It took a lot of effort to pull myself out of that rut including carving out leadership roles for myself and other tasks above my expected duties. This guy might have to similarly do a lot of work to catch up with market demands.