I continue to meet classically-trained brass players who also play cooler music on cooler instruments quite well, but who have built a wall between the two endeavors. None of them are happy about it. What gives, y'all? You've done all the hard work! Crossing over should be easy.
I was a brass specialist by 8th grade and a tuba specialist by 11th. I kick myself harder and harder over it as the years go on and my piano chops remain flaccid. Yet this also meant that I had no choice but to pursue the music I was interested in on the only instrument I was able to play well enough to do so. And of course, it was never in question whether the tuba and I were right for each other, even if other pairings could conceivably have worked out just as well. (Anecdotal evidence suggests that strings were not in the cards, though. I don't know how anybody plays those cursed things.)
In any case, I suspect our pedagogy is at fault. Brass playing in every style needs to become an art again (if it ever was before) rather than a craft. When it does, we will own our complete musical personalities on any instrument on which we have attained sufficient technique to do so. Walling will be a thing of the past.