Keys were added to bugles but they were still bugles. Valves were added to cornets and French horns and it didn't change their character. The Drum and Bugle Corps movement ended when DCI allowed the use of band instruments, which COMPLETELY changed the character of the sound. Gone is the crack of a contrabass bugle planting a downbeat like a bass trombone, and tubas can't replace it, even if you use 20 of them, all you get is a thud. Using actual bass trombones won't replace it, it just won't carry the punch. Bugles were used because they were LOUD. THAT'S THE POINT. Adding the pit made it difficult to hear the DRUMS and the BUGLES over the thirteen suspended cymbals, and electronics just added a layer of crap to what should sonically be a celebration of the awesome power of air and muscle. What does "You may take the field" mean when the sound crew making half the sound is in the stands?
Oh well, it was nice while it lasted. Enjoy the new High School Band International (HSBI).