In the early years, this sort of "Crisis, what crisis?" thinking set things up so that Mike couldn't help but see Lizzie as a threat. I'm of course talking about the fact that Elly was so busy paying attention to all the cute things that Lizzie could do, she failed utterly to notice that she was making Michael feel like he wasn't loved any longer. It clearly seemed to him that no matter what good things he could do, he wasn't allowed to take pride in them or receive recognition or be praised in any way because he's not a cute little girl Elly could dress up like a little doll. Trying to explain to Elly that she might be setting herself up to endure animosity was, of course, a non-starter. If she didn't blame the problem on him for being selfish, she'd make some sort of Peter Pan comment about how he magically knew that they loved him despite their active visible antipathy to his calling attention to himself.
The end result of this is his spending his life trying to call attention to himself by any means necessary. The other end result of this is that Elly is baffled by this because she doesn't want to admit that his life neatly parallels her own in that an oblivious thick-head mother turns a younger child into a love object while blinding herself to the fact that despite her belief otherwise, the older one is convinced that her parents don't really care about her any longer but are just keeping her around so they don't look bad in front of the neighbors. This leaves an unhappy world blighted with two idiots who've bullied their way into becoming the center of attention who sullenly refuse to notice that they're the slime axis about which their families rotate.