I don’t think the goal of the Design Sprint framework is to design a product. I think the goal is to design a business model.
I didn’t read the “Sprint” book, but instead followed the “Design Sprint” book by Richard Banfield, C. Todd Lombardo and Trace Wax. Following their framework — which aggregrates of a variety of Design Sprint methods — I ran 2 design sprints in the last couple of months, both with incredible success!
I think that “design sprint” is misnamed because the framework I followed was very holistic — it’s about finding a really big problem that a customer wants to solve, and finding a compelling way to solve it, including validation with customers on your entire business model (because you can also test pricing, marketing methods and other broader assumptions).
So, I agree with you that product design itself is not the panacea. But, I think the Design Sprint framework does touch all the right pieces of the business model to be a very powerful tool that I’ll continue to use.