Things change in this world, often in ways we don't anticipate. Although I think there is still much valuable work to do in developing the Na'vi language, it doesn't all have to happen at once. I have found that a lot of worthwhile projects, especially one as big as creating a useable, functional language, is an enormous, expansive effort. It takes a bunch of us to do this, and most importantly, it takes people using the language, and pushing its limits.
If you have noticed, I, too have backed off a bit. I had a sick cat to deal with since November (who died on Monday
), along with an ongoing, nasty regulatory battle. As important to me as Na'vi is, these real-life things take precedence. When these things tone down, I'll be more involved in the language. I have a deep commitment to the Na'vi language, and I never intend to give up using it or helping it develop.
You mention that this list has become a 'social club'. No matter what evolves and changes here, it will always be a social club, and indeed it has to be a social club to be what it is. If you notice, the vast majority of the fora here have little to do with language learning. Its been like this from day 1.
So in the end, you are free to do whatever you want. But don't forget this is a community. Even as interest in the language waxes and wanes, the community part (the social club) is a constant. You are always welcome here. Come and converse in Na'vi, in English, French or whatever. Tell us about your astronomy pursuits (and I am really impressed by how you have developed as an astronomer, and I hope you keep it up!) But above all, there is no need to simply turn your back in the community just because some of its pursuits have changed.