Yes, you're correct, Evelyn, a vast majority of people, once they reach the point where they've been full-time for a while and settled in to their new life, leave the trans support network. They don't need it anymore because, well, they're just living their lives as a normal member of society now. And there's honestly not a lot of support for post-transition people at trans groups, trans groups are more helpful for those who are going through the early scared phases of transition.
A vast majority of the trans girls I started transition with pretty much almost never come here anymore. They maybe make one post a week, if that. Most of the trans women I was looking up to when I was starting transition, they've long since left. Some have even deleted their accounts all together and gone stealth.
Hell, for all intents and purposes, I don't even need to be here anymore. The only reason I'm still here is because I like being an activist and like sharing some of my knowledge with others so I can hopefully help those who were in the same position I was in at this time last year. (I'd just been fired from my job, and I still wasn't passing, so I wasn't ready to go full-time, and I was FREAKING OUT.) I don't have any plans to leave personally, but again, it's because I like being an activist. I feel like it would be a disservice to the community to not tell my story and reassure people that it does get better, after suffering through all I suffered through and then finally emerging on the other side. But leaving is indeed the norm.