Yes, well...speaking only for myself, I'll say that life is too short to pursue some notion of "effectiveness" if the person promoting it can't (or won't) tell me what it's effective for. A hammer is an effective tool for driving nails, not so much for fixing a broken window. Should I practice against boxers? Maybe, but first I want a reason why. Saying that I should train to be "effective" against a boxer presupposes that that's a goal for me. So why should it be?
Simple; if you can't convince potential new students to take up your art the art will die.