Yes, BA drivers are poor at thoroughly representing the whole range of frequencies. That was the whole point of adding drivers and coming up with hybrid moving armatures.......to overcome that gross deficiency.
My points and real life experiences are well noted above. Onlookers can decide for themselves who's opinion is more convincing.
Keep drinking that Etymotic Kool-Aid!
Before I or some others point out what was wrong with your statement on "1 frequency", perhaps you should define what you mean by 1 frequency.