Anything that has any interaction with physical world is hard in comparison with SaaS-only business, hardware is not special in this. And in my opinion hardware

Anything that has any interaction with physical world is hard in comparison with SaaS-only business, hardware is not special in this. And in my opinion hardware is significantly easier than various shared economy or service startups, because in hardware your problems are still mostly about engineering and can be analyzed, measured and affected in meaningful ways.