In most large groups, there is a core group of members at the top and everyone else scrambing for rewards at the bottom.
This core group take the lions share of rewards (money, good jobs, attention, reputation). Everyone else competes for what's left over.
People usually accept this social order is based upon meritocracy. If people are at the top, they must have done something of merit to be at the top. This is known as a legitimizing myth.
Sometimes it might be true.
The people at the top may have done something of merit to be there, at least initially. Since then they have helped to perpetuate this cycle that benefits a status quo with them at the top.
For example, a conference selects a known person from the group to speak. This person brings their audience to the conference. By speaking, their reputation grows and they receive job offers from bigger companies. This makes them more likely to be invited to speak at future events* etc…
The speaker benefits, the conference benefits, and the hiring manager gets to say they recruited a superstar. Even the audience is culperable. Who wants to listen to a speaker they've never heard of?**
It's a great system if you're at the top of it.
The problem is the lack mobility. If people perceive social layers as impermeable they participate less. If newcomers don't believe they can break into the top clique, they either leave or become silent followers (lurkers).
People will always eventually tire from the top group and look for places where they can move between up the social status ladder.
Every community will have a clique. In itself, it's not a bad thing. It's a group of people that know each other. The problem occurs when that clique is at the top of the social ladder and strangling the opportunities for others to emerge.
In every single gorup, there are newcomers doing exciting things and with new ideas. The great opportunity is to take the social risk yourself, as a community professional, and throw your support behind these people. You usually have to seek out the very people doing the things the clique dislikes and promote them.
The people at the top will denounce their ideas, attack the newcomer's lack of experience, and challenge their work. That's going to be annoying. But in the long run, it will work out far better for you and your community. You get to prove the wall are impermeable and, perhaps, that rising up the social status ladder really is based upon recent merit.
* In fact, many conferences select speakers via recommendations from existing speakers, a rather overt form of status quo collaboration.
** Often the audience knows what the speaker is going to say, they just want to hear him/her say it.