This is complicated by her delusion that she's somehow impressing Marian by doing the same stupid things to Mike and Liz that her mother did to her. Somewhere during the overly long visit, Marian must have listened to her words come out of Elly's mouth, seen Mike react the exact same way Elly did, watched Elly get just as upset over something she should have handled better and realized "HUM!! No wonder that never got results! Acting like Elly was some kind of leper I was too good to talk to doesn't God-damned work and never did! Ah, well. Elly's smart. She'll figure it out soon enough." What Marian never seems to have realized, what she died never knowing is that Elly clearly thought that the more she acted like her mom, the better a parent she was and the more impressed she'd be with her.
What this, of course, means is that we're in for another twenty years or so of Elly losing her shit because her children's rooms show signs of human habitation and said children don't seem especially perturbed by that fact. What it also means is that Elly lives in fear of a parent asking "When the Hell did you become such a stickler?"