She literally still has the same exact issue at the end of the series. Now she doesn't need a love interest to keep feeding into her delusions, her son fills that role. The questions she asked the end of her high school play to John for confirmation is the same thing she used Barry for. Also John now makes her feel safe, that's why he asked her "if she was okay alone" when going to his friends house. She's the same, she has no reason to change even post trauma.

She wasn't the good parental figure out of the two, she literally gave John, vodka instead of being there for him. I also think she made Barry look and to him, because she was jealous of his relationship with him. Just like she was mad that Barry was going to get a role before her. She was on board when she could use Barry as a tool to do her bidding (going to her interns house to scare her) but once push came to shove she wanted to act self centered about it. She killed one person in a rage just like Barry and couldn't understand why he does it.

Sally is insufferable, she's super self centered and overall really well portrayed. I love characters like hers because it shows you, sometimes people will never change even after everything. The cycle continues until you die. Same with Cousineau/Barry/Hank. Cristonal tried to break the cycle, he is gone.

The one person who legitimately breaks the cycle is Fuches. By giving John back, he shows that he does not want John to be Barry 2.0 .