Our life circumstances are nothing alike but I think we're in similar boats. Only reason I haven't CTB yet is that it would hurt my husband too much, I don't think anyone else would care. Something in my brain is very, very ill-suited to its environment, nobody knows how to fix it, and everyone keeps telling me all I have to do is commit to $PET_TREATMENT and it'll get fixed. Since it seems like my ticket has been, if we're being honest, labelled WONTFIX, it seems a bit futile to hope for a patch.
I think a large part of it might be modern individualism and globalism. You are right, for better or worse tribalism is real. They say about half of happiness is genetic (I guess we just lost the lotto here) but strong community bonds are known to be a major component of "environmental" happiness. I left my "tribe" too, probably very common nowadays when all the good jobs are in a few cities. It's at the point now where I've moved around so much I don't really know if I can say I have a tribe or if I ever did. I'm trying to fix that now, to integrate myself into a strong community, but it's very hard. Would not bother if not for husband, I'd rather just lay down and sleep forever. It all just feels like a lot of work for not much payoff.
I dunno what else to say, I guess you have to pick a path and go with it. If you still fear death it's probably a sign you're not quite ready so I guess you may as well double down and keep trying. It's not like it really matters if it burns you out to the point of no return, if your other option was to kill yourself anyway.
So how many decades were you depressed for, what got better for you, and what makes you so sure that this thing A. gets better for everyone and B. will fix their depression? Objectively, for some people, it does not ever get better. If you are being honest, then you surely know it's possible for life circumstances to get worse and worse over time until that person eventually dies. For others it will go up and down and up and down, and for others it will be pretty "meh" in perpetuity. "It gets better" has to be one of my most hated platitudes. I am glad "it got better" for you but it would be polite not to rub it around in people's faces.
Not to mention, much of a person's happiness is supposedly determined genetically. To me it seems very cruel to give people false hope and then tell them it's their own fault when it doesn't pan out the way they were promised (which seems to be the usual way of things). I've been hanging out here for 15 years for my suicidality to get better and I haven't been passive in my waiting. I've tried a wide variety of things and some help for a little while but none really stick. For how many decades must I continue to hang around before the "it gets better" types can be honest enough to admit that sometimes it doesn't?
Just like everything else in the list of bad advice, it's something that most depressed people have already considered or tried, and either are unable to try it (for financial or other reasons) or tried it and it didn't work. People who have never been through that wringer seem to be under the impression that depressed people just need to get on some medication and go to therapy for a little bit and they'll be fixed. Would be great if true, and it is for some people, but definitely not for all people. Even if there is some unique combination that would work for any individual "hopeless case" (which is doubtful), there are just so many different medications and therapies to try, and most of them need to be tried for a few months before you're allowed to say that no, it really isn't working. And then you are supposed to keep your chin up and move onto the next one, and the next one. It gets very exhausting and demoralizing for someone who is already chronically exhausted and demoralized.
It's an especially evil piece of advice when offered to friends and family. Many depressed people lack the physical energy and willpower to put themselves through the psychiatric system, again and again, without any support. If I believed in hell I think there would be a special place in it for people who tell their loved ones to "seek help" when those loved ones are currently, by telling them, trying to seek help.
Honestly sometimes it gets to the point that I don't even want to spend time around other people unless they are equally chronically depressed, because you can't have an honest conversation with people who aren't. They either go into pollyanna mode or tough love mode and neither come from a place of actual connection and understanding. I think it's too scary for them to try to understand so they don't really try, and we get a multitude of platitudes that don't do anything except maybe make the giver feel better about themselves for doing a "good deed". If you explain why the platitudes don't help they usually just get mad. I think suicidal people spend more time doing emotional labor for non-suicidal people than the other way around. And then they call us selfish for leaving when we've finally had enough.