That's not true. This is a disorder that is a tough one, and treatment is often very lengthy. Those of us who do research in this area are trying very hard to find more effective and efficient approaches. We need to treat each child individually. A speech pathologist will look at a child's speech pattern and often by doing an articulation test and developing a profile of the most frequent kinds of problems for that particular child.
Some children have problems with sounds in simple words.
With other children you don't see the problems until they pronounce multisyllabic sounds, for example. The treatment will depend on the problem for each individual child. In this article I mentioned before, Penny Hall's article, she discusses different treatment approaches, and as I mentioned before, I work mostly with the motor programming approach, trying to find effective ways for children to learn, or relearn, accurate sound production. One thing that research is showing is how important feedback is to children and adults. It's very difficult to spend lot of words trying to tell the child where to put his or her tongue, et cetera.