You don't need a clan to get better, make friends on here and help each other get better. Sounds to me like the clans are old skool and getting soft so they don't want to play some of the newer cocky players for fear of a loss. (Unless they have Super Campers on their teams)
You cracked the mistery bro
Doubt any clan wants a newer player that still isn't that good with a cocky attitude for starters... The matching scene doesn't really let that many new people in because it's stuck to a few decent players that know eachother and play together, eventually people get tired of playing the same people over and over again so they just end up leaving.
Not accepting new players in the clan has nothing to do with fear of loosing or needing super campers to prevent loosing (that sentence made no sense btw) it's because they don't know them and don't bother getting to know and train them
Every now and then new guys start playing and end up getting good and getting active in the match scene... It's a long shot tho
Number of people leaving > Number of people joining the matching scene
Simple as that.
PS: Hi there
-- even if the topic is from may and you're most likely no longe around