Perhaps a lot of that situation is a Western phenomenon. How many people in our "gotta get it now" society are committed to a long-term, deep -- even lifelong -- pursuit of something so esoteric? Especially when an external kick, punch or joint lock is instant gratification?
Maybe the "moral-ethical" question is, does one offer it up to all comers, in hopes that some will stick it out and learn fully? Continue to be a voice crying in the wilderness?
Or does one save it and "give" it only to the ones that prove their mettle?
In the ideal world, I'd love to see it re-integrated into aikido (which, of course, would change the way aikido is done, and looks) and elsewhere where it "should" be. In our hi-tech age, to keep these things as "secrets" does not serve the purpose it did 700 years ago, when family combat systems meant life or death to a clan.
Given human nature, I believe that the mainstream and its "good enough for us" curriculum will always be the norm, while the deeper skills will persist and be perpetuated in small, relatively obscure pockets. But rather than be cynical, I choose to accept that not all knowledge, no matter how elegant we think it is, will ever be given its due. It's there for those who truly seek and want it, though.