(Note -- I am intentionally leaving Marigold out of this post because bottom line is that she is young enough now that being pulled from the Drewes is not something that will be in her memories. My opinion here is 100% about Edith and her decision.)
Speaking as a single woman with no children, husband, or close family, I completely disagree -- this is a HUGE personal victory for Edith. She is celebrating her decision to finally take control of a situation she has felt has been out of her control since she left Marigold in Switzerland. She went along with the decisions because that is what a proper lady of the time was supposed to do, and the role she has always played in the family, even though she knew in her heart it wasn't right. Just because you don't have someone to have that celebratory glass of champagne with doesn't mean you shouldn't have it! Why deny allowing yourself to feel happy and be proud about something you've done simply because you are alone?
Why do you need someone else there to validate that happiness or make it a "real" celebration? She is toasting herself and her decision, and she doesn't need anyone else there to do that.
It drives me crazy when people think that its sad that I do things on my own because I have no one to do them with. Guess what -- I'm not missing out on anything I want to do in this life -- be it see a movie, travel, or drink champagne to celebrate a personal victory -- simply because I don't have someone to do it with. I have single girlfriends who won't do things because they are alone, then the complain that they missed out on whatever it was. Get over it, and just go do what you want to do. Screw what anyone else thinks. Meanwhile, I've travelled to Hong Kong, Thailand, London, Paris, and done some really cool stuff, all by little ol' self. And I have, on occasion, had a glass (or bottle!) of champagne to celebrate something in my life. All by myself, with no one else. And it wasn't sad, or depressing, or anything else negative. It was having a glass of champagne, being happy for myself, and not needing anyone else to validate it, or make it "real" or anything else. Being alone diminishes nothing.
And that's what Edith has finally done for herself, for the very first time -- she said screw what anyone else thinks, I am going to do what is the right thing . . . for me (and by extension, Marigold) and no one else.
I see this as a potential character game-changer for Edith. Not that it will happen this way, but she's finally stood up for herself against an entire life of being dismissed, put down, told what to do, and basically being given no chance to shine or be her own person, always cast in the shadow of Saint Mary. Hopefully, there will be no going back to being Sad-Sack Edith.
Trust me, although I'm not a middle child, I know from experience that sometimes the ONLY way you can find out who you are, stand on your own two feet, and be true to who YOU are is to completely walk away from your family. You know who you are and no matter how hard you try to show that to your family, the role they think you belong in is the only way they will ever see you -- and they will do everything in their power to keep you there, especially when you start to divert from the role they've put you in, through no choice of your own. And they won't understand when you reach the point of feeling like you have to leave for your own sanity and survival. And even years later, they will still pigeonhole you in the role they cast you in, regardless of whether that is, or ever was, reality. While its a nice idea that families support each other and lift each other up, that is not reality. If you had that, congratulations. Not everyone does. I didn't, and Edith sure doesn't.
Edith is happier and more confident when she is away from the pigeonholed role she is put in by her family. When she made the decision to write for Gregson's paper, it was essentially against her family's opinion (mainly Donk's), but she was happier because of it. Every time she tries to offer a glimpse of herself, the things she does or wants to do to show who she is, the family puts her down, dismisses, or criticizes her for it. By doing what she's done, she's finally said, "enough of this bullshit."
Even if the family decides to "cut her off" in an attempt to bring her back (again, trying to maintain control over her and trap her in the role they've assigned to her, whether she belongs there/deserves it or not), she has Gregson's paper now, and has income of her own.
For a woman of that time period -- especially an unmarried woman -- what Edith has done is MAJOR. She has taken the first step to be an independent woman, free of her family, who is going to live life on her own terms, regardless of what people think. That is huge for anyone, but especially in that time period? Order a magnum of champagne, Lady Edith, and toast yourself with every glass!
She finally took a major step to take control of her own life -- maybe not in the best way, but when you've never done it before and are changing bad-for-you situations that were created by others, you don't always do things in the best way possible -- at that point you feel like you are doing whatever you have to in order to find a way to survive -- you do whatever it is you can think of finally, for once, do what is right for you and no one else. It is terrifying when you do it, and heady when you realize what you've actually done for yourself, for the first time ever. What ultimately matters is that she did it.
I say raise that glass of champagne to yourself and your decision Edith -- you deserve it, and earned it -- who cares if anyone else is there to celebrate with you -- this is your moment -- the first one that is truly yours alone. She doesn't NEED anyone else to toast with her -- it isn't about anyone else but her, for the first time in her life. Having someone else to toast with would, in my opinion, diminish the importance of what she's done.