That's an interesting point regarding the duty times. What's the point in having an A & P if due to duty time restrictions he often can't fix the plane. I imagine a lot of operators just turn a blind eye to duty time in those instances and have him fix the plane regardless as the need arises.
Still, given that most real PFEs are older and nearing retirement age, you'd think there would be some demand for them given that a lot of operators are still running the old Jurassic jets in the 3rd world...