The book, The Brain's Way of Healing, suggests modest improvements in a (similar) framework result in more hope which turns into a virtous cycle. Sounds like an overlap with your comments on appreciation.
I don't think it'd work or be appropriate if the depression comes from basic missing pieces in their life - a partner (or at least faith they'll find one one day), work they find fulfilling, their day-to-day interactions with others are tolerable etc.
I think depression is the mind and body's way of telling the subject " you have to go a different direction". This is consistent with it deenergizing and demotivating them and making it harder for them to prevail in their goals - this naturally arrests further progress in that failed direction, and sends them looking for answers on how to stop feeling depressed (which if our culture was good in this area, would send them off down different life paths rather than to drugs).
I think it can. That was sort of my point. It’s not about having all of the things you (think that you) want. It’s about having the things you appreciate.
The working out, the meditation and all that shit is not meant for the health benefits. It's so that you'll appreciate that you're slightly healthier in time, or slightly more mindful, etc. Teaching appreciation of the things you have and have achieved.
There is a direct line from the explosion of modern depression to social media (particularly Instagram). Social media is entirely about envy of others, and as the saying goes "envy is the thief of joy".
The point of a happy, fulfilling, depression-less life is not to have everything, it's to have something. Particularly "somethings" that you've worked for.