I think you're misplacing blame for this, I don't think the engineers are the root cause of this problem. Why don't these devices let people set their own custom codephrases? I suspect that wouldn't fly with management/marketing etc, who want to create a marketable brand out of the codeword. In fact I'm virtually certain that engineers at amazon weren't the ones who chose the name "Alexa" in the first place, that decision probably went through a dozen squared meetings and committees of marketers and PR people.