Perhaps I'm being defeatist, but I think it may just have run its course.
We've had people grow up on this board (sort of). We've seen RickyG and Billy Goats Mates transform from callow youths to responsible parental units, we've seen people go through marriages, divorces and all sorts - we've even seen Fash settle down! And inevitably as those life things happen, people will tend to drift away. The problem is that, whereas in the old days new blood would come on here, nowadays a message board is bound to look hopelessly outdated to kids who've grown up with snapchat, Instagram et al and they're not going to come through.
In addition, this board's fortunes have very much mirrored Wenger's career arc with us. Its peak was during his peak as manager and, as our fortunes have declined relatively, so has interest and participation in the board. There simply isn't the buzz around talking about an Arsenal in relative doldrums that there was about talking about one that on occasion looked like the best domestic English side any of us had ever seen.
So yes, I do think perhaps we're seeing the natural decline and likely death of AWIMB. It's not been killed by anything, it's just had its time.