"As many experienced engineers know, although the maximum power transfer theorem is an interesting result, its usefulness in practice is extremely limited. A few electrical engineering books and articles have discussed the lack of utility of this theorem in specific applications, but its supposed importance is still claimed or emphasized in several textbooks and numerous articles. Indeed, the theorem has such a religious aura that one might be led to believe the use of the maximum power transfer theorem will solve all problems."  (Taken from  McLaughlin, James C. and Kenneth L. Kaiser, Deglorifying the Maximum Power Transfer Theorem and Factors in Impedance Selection, IEEE Education Journal, Vol. 50, No. 3, 2007.)