Personally I've seen a great many fly tyers that once were the main sages of forum drop out of action--gone AWOL if you will.
Of course there are still a few of the old timers around, which is a good thing.
Usually is how it works (from what I have personally observed)is someone joins, maintains a steady attendance for a while, and then is gone to who knows where. This is obviously due to the undebatable fact that life does indeed intrude on enjoyment.
While I don't consider myself an old timer (I'm not sure if this term refers to time spent on the forum, or literally aged fly tyers), I used to be a fairly steady poster for a couple years. But, life simply gets in the way sometimes.
Personally, studying is a big part of my life right now.
And that, paired with the crowd of other non-piscatorial activities takes up much of my free time.
I'm afraid fly tying generally finds last place in these sort of things.