I'm not sure if the clan world is shrinking, but it is changing. Like Y Guy said, most clans don't even look at people who have 0 clan experience and won't take the time to teach these people or recruit them. With that said, there are fewer members coming into the clan world in a lot of cases, and when you get the majority of members in a clan solely playing for that clan and nothing else, and the clan closes, there goes a lot of clan members. However, many people overlook the numerous small clans that form which i think keeps the balance.