As you know, the Patterson family seems to fear one thing above all else: confronting people who have offended them. This stems from the children copying how Elly herself reacts to her surroundings. It doesn't matter if it's the real or retconned past we're talking about, Elly seems to want to avoid any real sort of argument that might resolve an issue permanently. She'd far rather hem and haw so that she can enjoy feeling victimized. Mike was able to take advantage of this to more or less get his own way because he knew that if he held on long enough, Elly would fold. At the same time, of course, he was fairly passive himself. The only people he successfully dominated were Liz and Deanna because they had even less willpower than he did. Not even John is able to really stick up for himself; instead of facing what went wrong in his life, he played with trains.