For all I know, this guy may actually be some product visionary, but why isn't he telling this vision to designers to create the mocks so the intricacies are worked out before it gets to build? Is it because he doesn't believe this process would move quick enough?
Also, one huge flag for me is that not once in your post did you mention that his "vision" was based off feedback of users. This is the most important task of a product manager (collecting user feedback & filtering it back to engineering). In the past, I've also had hunches about how things should work & I've proven myself completely wrong either after asking users or in usability tests on the build I designed.
Remember, Steve Jobs was designing products for the average person - not a lot of startups target such a blanket market & most are targeting some subset niche. You really need to be a voice for the users you're targeting.