It could be the laws of physics Alan, if it were not for the Yamaha type of design I would accept my fate.I think you would agree that the Yamaha responds just as fast in the lower register as it does in the very highest?
Looking at the Yamaha and others with the same basic design where you have a row of reeds that you blow directly across covered by a very shallow concave cover I never have a reed response problem.
The Hohners and I believe also the Suzukis have a large rectangular cavity that you have to fill up with air before the reed will sound. I believe this design is what’s creating the delayed response as well as the design of channeling the air to the highest notes first?
I’ve done some experimenting on the Hohner Performer 37 (meant to get a video up at some point) where I applied putty around the inside air chamber reducing the size and shape of the area till it’s similar to the Yamaha design.
I now find the Performer 37 has a much faster and more even response across the 3 octaves.