Joseph:
Your facts are obsolete, if they were ever accurate.
Today’s world of psychology is based on empirical data. For the overwhelming percentage of recognized and accepted practice, there are volumes, even reams of research that support its efficacy. We are long past the times when theories became popular and entered mainstream practice. Special ed has the luxury of being even more founded on scientifically proven techniques. There are several reasons for this. One notable one is that the success or failure of a technique is more easily quantified and observed.
Psychology has always been a science. It is a softer science than engineering, and thus subject to refutation and newer discoveries. This happens in the hard sciences as well, as perfection is not common among humans. But you overplay the minimal amount of inaccuracy or lack of efficacy. Sounds like you have an agenda.
The OP’s point is that our mainstream yeshivos can easily be more inclusive by providing a wider array of services. Some of this requires additional staff with specialized training. Other ideas might be better training of the regular staff/faculty. Both of these are likely to meet up with considerable resistance. So even to the degree that we may agree with the OP, remaining skeptical that these ideas will fly is predictable.