You are saying your boss goes to the trouble to get a working prototype going and even does the UI fronted and when he asks you to finish and scale it out as an engineer (which is your job) you take offense to this request?
It doesn't really sound like the boss is providing a working prototype. It sounds like the boss provides throwaway code that is a step or two better than a screenshot or whiteboard drawing.
He's frustrated that his boss is basically doing the equivalent of, "I heard about NoSQL at a conference today, all our competitors are using it, please switch us from MySQL to NoSQL. It will be great"
(Then a week after the switch is done; "Have you heard about postgresql...?")
