Navy It sounds like she may not hit rock bottom, but maybe she hit a branch on the way down, and the pain is enough for her to try to grab on to the sides of the pit she is in, and climb up a little.
Ok odd metaphor.
Here is what I really mean, so you backtracked a little. So what, keep finding your non negotiables and keep pushing to get what you want or for her to leave.
Even if you agree to throw her a rope, it's ok to change your mind. She'll demonize you for it, but it's being true to yourself.
Remember she knows you want to be the good guy so she will paint you as the bad guy to get her way, because she knows you'll break at the slightest hint of you being a jerk.
Yet on the other hand you were the "jerk" once and.....she cut down her drinking!!
It may not seem like it but that is huge!
It means that she may be too stubborn to admit she's wrong, but not too stubborn to realize she's about to kill the goose that lays the golden eggs.
So she will try to throw you a bone to keep you without having to love you. Don't forget the goal, to get someone (whether it's her or not) who wants to stay with you because they love you.