Objectivity as one of the most important components

Usually, unnecessary work means "we could have done it ourselves." The uselessness also lies in the fact, and this is a feature of the consulting itself, that the results of the work of consultants are often not immediately visible. The effectiveness of the decisions made can be assessed only after some time, and often it is impossible to determine exactly what caused the improvements. The management of the enterprise often thinks that it was it itself who was able to correct and improve the situation, and the consultants have nothing to do with it. In general, this question is more historical than rhetorical.