I wouldn't go that far. But there is a fundamental problem with language teaching, and it is one that I don't believe has been studied or acknowledged and certainly doesn't form part of the curriculum in foreign language teaching MAs. It is not confined to English language teaching. It is this:
What other discipline can one teach when one has not gone through the explicit learning process oneself? We all learn our native language before we are even conscious of who we are. Nobody teaches it to us. And we never consciously learn it. So, when we try to teach it to someone else, we are trying to help someone master an intellectual discipline that we ourselves never had to consciously master.
If we are a maths teacher, we explicitly learned maths at one time in our life. We struggled through the intellectual process and we got there. If we are a science teacher, the same. Go through the list. On the other hand, teaching a language which is, for us, native, whether it be English or Spanish, or any other, we can only guess at what the student is going through. I have often wondered if there is any other teaching discipline where the same situation applies. I have yet to come up with one. It's really quite odd, when you think about it. Yes, explicit learning of English grammar is an academic discipline that we can consciously study and conquer after we learn to speak English naturally as a child. But, a basic TEFL or similar course doesn't teach us much formal English grammar and nor do equivalent teaching courses for other languages. And the dominant communicative language teaching philosophy we study in basic and masters level courses language teaching courses doesn't put much focus on the finer points of grammar.)
If I were looking for a language teacher to help me learn a new language, I would look for one who is a non-native speaker, i.e., someone who learned the language to a high enough level that she can help me, and who, therefore, went through exactly the same process I am setting out on, and who will know exactly why things don't make sense to me--because those same things didn't make to them when the first bumped up against them.
Not a popular view, and not one that many language teaching schools are interested in (they say the students want native speakers). But that is my opinion.