Autism is a disorder of neural development that is characterized by impaired social interaction and communication, and by restricted and repetitive behavior. These signs all begin before a child is three years old.

You are ignoring regressive autism, which now accounts for the great majority of cases in the UK and typically strikes a few years later. "Autism spectrum disorder" is a wider category again.

Most of the patients my girlfriend treats have regressive autism - they tend to be a bit atypical (not sure how many she's dealt with, must be well into triple figures). But it's very rare that no combination of treatment approaches achieves anything, no matter what kind of autism they've got. Parents often give up, though - often with more reason than the parents of hyperactive kids, since the gains can be minimal and require enormous effort.

As regards our Autistic daughter, we have been working with her since she was 3 and was statemented at 3 and a half, and is now 14. I and my wife have worked very closely with the specialists and I have done a lot of Home teaching based on what the specialist were doing and today, she is in mainstream with support. She can talk the hind leg off a donkey. She can read very well. She, through a lot of hard work in her early days, can use the computer proficiently and much better than most older people. Thats becuase we and the specialists have put a lot of hard work in over the years. [...]
Please realise that their are parents out there who have literally give up their lives to support our special needs children and for you to make such glib comments, is not appreciated.

I don't see where you could have read anything I've written as attacking you for making that sort of effort. You obviously aren't the sort of parent who ignores all expert opinion and treats their child as a guinea pig for a theory of their own. I am simply pointing out that for some autistic kids a better outcome might be possible, or the same sort of outcome with less work. Not all autistic kids are the same. For others the reality might be much worse, 15 years of heartbreaking and totally wasted effort ending in no gain and no future. You can't generalize.