Don't know why you care, to be honest.

Most people who leave do so quietly. Those that announce it as if it's some form of retirement from a career are usually those that come back after said announcement anyway.

Personally, I won't quit - As I'm far off from accomplishing everything that I want to, especially since I'm casually achievement hunting, which means my 'content' is spread all across the place. But I do think if the next expansion is to be this 'thin' then it might lead to me less frequently playing, or just spreading myself across more games.