There are some other reasons to say too along with them. Also, at the same time, don't want to look rude but Theymos doesn't really take care of this forum. I don't judge it, I really appreciate bitcointalk and its role in my life, it completely changed my life for better but truth is truth, this forum looks like abandoned and the major life-giving power is the signature campaign at the moment.
Bitcointalk needs serious change, implementation of new features to make the website look like a comfortable all-in-one service.
Also, I'm not sure I agree with your opinion here. theymos isn't very public about his work put toward the forum, unless it needs to be public. I think he's done a rather good job over the years. A lot of users would have become overzealous with their perceived power, and I don't think that's the case here. Lack of changes doesn't necessarily mean inactivity. There's a lot more going on behind the scenes than just changes. If anyone has ever ran a website with moderate success, they'll understand that there's general maintenance that needs to be done. Also, I suspect that theymos has a fairly active life outside the forum, which is also understandable.