Altcoinstalks is one of the stupidest forum that I have ever been. The forum is still alive because of the discipline from people on this forum and nothing more. The forum was full of wrong information and dilapidated until this forum banned mixers. Their Karma system is faulty and worst than those social media likes.
You are right, I am active on altcointalk and I can say that most and all quality contribution there are all from teleported accounts who's user names I am mostly familiar with from this forum, so for sure, without Bitcointalk forum members, altcointalk will be a dessert place for quality posters.
What I have noticed with the Forum altcointalk also, is that, most of the feature there are directly opposite what we have here for example.
Bitcointalk is Decentralized to some extent, theymos have little involvement with a lot of thing's, leaving the member to act with sense of freedom that align with the core mandate of Bitcoin.
Altcointalk, have an admin that is 100% in control of the Forum who act and members just have to obey, somewhat like a market place where you have to pay for all and almost everything, including deleting your own posts