It seems like the only reason P buys as much as she does and then it doesn't last very long is that she makes such huge portions at one time for everyone. Sometimes she has said she likes to have leftovers (to give to Abbie). But it really seems like the truth is that she makes enough food to feed like 12 people in one go. Everyone gets huge portions on their plates and probably almost all of them go for second helpings.
I don't entirely think the reason is that she's hopeless to learn. I think it's the same reason it always is, it takes a lot of time, effort and consistency which A&P are just too lazy and unwilling to do. I think they could have gotten a lot farther by now if they had figured out a regimented plan and just stuck with it. Not saying Abbie would be perfect. But I think things would be a lot better.
Plus, other members on this board have mentioned that autistic indivduals can have issues with mind & body connection, knowing when they need to go to the bathroom, knowing when they've had too much food and they're full.
You nailed it. I think this is true for pretty much all kids. They will misbehave if you've been ignoring/neglecting them and do whatever it takes to get your attention. Sadly, it's usually bad behavior that gets the quickest response. I think this is true for Abbie, in addition to her lacking discipline. Like you said, Abbie has figured out what gets A&P to pay attention to her the quickest and that's to act out in a negative way.
I keep seeing comments saying that Abbie is just too far gone or past the point of help. I really just don't think that's the case. We can all agree that A&P do the absolute bare minimum with her, they don't put in the time and effort, they're not consistent, they don't engage with her one on one and just give her some positive attention. That has a HUGE impact on Abbie being the way she is. I also think that Abbie being stressed out, anxious, and frustrated by quarantine life and any kind of schedule or routine being uncertain and unpredictable, that affects how she responds to the tasks being asked of her.