If an adult wants to learn how to fight/defend themselves fairly well within say, 5 years of part-time training - they won't get there thru kata training at the majority of kata-centric dojo's.

That statement says nothing of kata worthiness...it speaks more to the worthiness of schools claiming to teach self-defense using kata. therefore, the argument of kata effectiveness is mute. If the majority of schools don't understand kata well enough to utilize kata as a training tool for fighting principles and self-defense, then clearly kata training as a vehicle to teach civilian self-defense to the masses has failed the test of time. or has it? If you look at as it not being DESIGNED to be transmitted easily to everyone, then it has in fact, stood the test of time. Depends how you look at it. On the other hand, what good is a self-defense tool that is only transmitted well to a mere 1% of kata practitioners?

The simple fact is, the only way kata can be trained and transmitted for the purpose of self defense is up close and personal with an instructor constantly watching on....and I would argue, either a span of full time practice - or a much longer period of part-time practice.

Kata movements are mainstream. kata substance is private.

Why is it the best teachers do so for free but yet have few students?

the answer is because 1. they aren't looking for students. and 2. the majority of people don't actually want to invest what is necessary to learn an Art in-depth...the public are dabblers and are satisfied with the superficial. 'who wants to learn how to breath correctly, thats boring.' no. first, thats part of the Art and second it happens to be well founded if not central to fighting principle.

but when too many customers...I mean students, moan about it - it's eliminated from the curriculum of what is taught for the sake of retainment and 'student' satisfaction. then the next generation of teachers don't even know there used to be breathing methods...so it gets lost.

so butterfly, I agree with you. who needs kata if they just train it as a bunch of separate responses. Your Ashihara style trains the actual techniques used, not some reversed engineered made-to-fit interpretation. even if kata 'bunkai' trainers get it working, it's no better than the method of non-kata training! I completely understand your 'it comes down to preference' view.....it's an excellent and solid point.

I can't claim proof. but I can honestly leave it as: The reason I still practice kata is to continue learning a very elusive Art. If kata does nothing else than open the imagination to possibilities, wasn't it a worthwhile journey?

for reference:
http://www.fightingarts.com/ubbthreads/showflat.php/Cat/0/Number/15801330/page/0/fpart/1/vc/1

Miyagi Chojun's best kata advice: 'keep doing it, you'll figure it out.' -you have no idea how diabolical that advice is. It leads the student to believe there is a 'goal', a one-size-fits-all answer, when in reality during the time you are thinking and working it out, and learning how to teach yourself your 'customized' form. invisible in plain sight. kata does change when someone who truely knows it well enough to use it, teaches it.

but there is something else... I can't give it away, since it's not mine to give. even if I could, I can't think of a worse medium than the internet to transmit it.