I produced a hub to celebrate 100. I had a list of people that I was honouring and many came from the top 200 of new hubbers last year. By looking at my broken links, it looks as though many have just left. It seems that hubpages do have a fairly high turnover of people, although many might not frequent the forums anymore, their accounts are active.
Many of the people that I used to enjoy a ta-ta-tate with here, are no longer around
The good news is there are always newbies that we can help, watch them develop and enjoy! 