This is so absolutely true, and a lot of visual designers are trying to fake it til they make it as product designers because that’s where the jobs are, and then they are basically trying to take a crash course in how to be a product designer once they’ve convinced someone to hire them.
Discussion
I think good product designers have a broad background in adjacent fields of marketing, business, psychology, people skills, copywriting to name a few. And of course a strong core design competency. UX designers may not.