Because TIDA (and other groups) are using dogs that the NIS would definitely NOT use - such as those with epilepsy and serious breed faults. Also TIDA (and other groups) still allow crossbreeding in their programme whereas the NIS do not.
Surely a breed which is losing type due to BYB should be suject to the same rules as any breed in progress. In this thread people have said the key to a breed is conformity. If this conformity is lost then should the breed not lose KC regonition until a type is developed again. Methods of breed contol used in the past are just not practical now, we can not cull puppies and neutering all dogs going to pet homes before they go is extremly impractical. You can not hip score until a dog is over 12 months and in some cases it can take 18 months before a dog evens out and the conformity to type can be esablished. Keeping all dogs until they are 18 months old wouldn't work and people would still want puppies which would give bad breeders even more bussiness. All pups sold by an NIS breeder go with documents to join the NIS free and also the owner must sign a contract not to sell the dog on. By the new owner reg with the NIS the society can keep an eye on the pups. Some people may not join but to most people do so as to become part of the NIS community.
Also some dogs turned away from the NIS as breeding stock then just go running to the TIDA (and other groups) to be reg. The NIS has a much tighter control over which dogs can be used for breeding and the NIS reg breeders have to follow a code of practice.
Can't comment on the past development of the NI but from what you suggest the whole process is out of hand and the chance of the development of a breed that could be recognized as a breed is fast retreating. Think as both you and SallyinLancs seem interested in the genetics and breeding of dogs you could try some books on the subject and looking at the web site of the chap who produced the bobtail boxer may be worth a look as well as you are also interested in the breeding of new or changed breeds. http://www.steynmere.com/ Link for the Bobtail Boxer
It's definitely a difficult situation and I can't see NIs becoming a KC recognised breed in the foreseeable future. However I am more concerned with the breed itself than KC recognition and as the NIS has a few years on the other groups (in terms of its establishment), I hope that a few years down the line the differences will become much more obvious to the wider dog-world and the general public.
As explained before, even a badly bred dog, still looks like the breed it's suppsosed to be ! Therefore it is still "Recognisable" hence the term to be KC "Recognised".
I disagree some badly bred dogs do not look recognisable as being of that breed. It some cases it down to markings and coat type so people make a judgement based on what they think it could be.
I hope you get your wish but it will never happen if they keep out crossing without any plan in place. Where do you start, there is such a mishmash of dogs out there all being called NI or one or the derivatives. Also think that perhaps aiming to produce a large companion/utility dog for aesthetic reasons only may cause problems, there are limits to how big people want their housedogs.