As far as the perfect trumpet being non-playable - most definitely not. A trumpet is a musical instrument that uses the laws of physics to its advantage. It is not a technical masterpiece that ignores playability.
In fact, a horn flare can be perfected for a specific goal. In the case of a trumpet, it is not even there to amplify. It is there to change the acoustic length of the horn dependent on frequency. Buzz on 9 feet of 1/2" tubing without a bell and check out how out of tune the octaves are......
It is possible to increase the "slotting" or Q of the resonant system. Then it becomes difficult to play in tune. It is possible to increase the throat reactance of the horn, then the player suffocates because their exhale cannot get rid of the air in "human" intervals.
Nope, the perfect trumpet is something not created by aerospace engineers with no ears. It is created by an artist with engineering saavy. Google Richard Smith from Smith-Watkins cornet/trumpet fame. His technical knowledge did not get in the way of his designs!