Why quantum mechanics?

It has become fashionable to say that all electrical engineers, or at least those specialising in communication engineering, ought to be familiar with the basic ideas of quantum mechanics. In view of the ever-increasing load of university teaching, is this statement justified, and, if so, why? A reasonable case for the teaching of quantum mechanics to engineers can be made, and some simple ideas and mental analogies can be developed which may prove to be of use to electrical engineers.