A solid question IMO. I believe that anything that has a visible solution to a problem for a customer can be categorized as a product. And it doesn't necessarily have to be a digital or software solution. It could be tangible physical item meant to ease or enhance a task, or a service provided by someone with measurable outcomes. Regarding software, as long as it brings ease of life or solves a real problem, it can be a product.
Would love to hear your thoughts. Thanks.