Most people stay in volunteer based organizations for fraternity and a social life.
Lately more options are being presented for social networking on the internet. Even this website has its meet-ups (mini-conventions).
The motives of the rank and file of volunteer organizations cluster around sharing common experiences.
Kids that were raised as JW's and left still seek each other to hang out and swap stories about the crappy assembly food (in some cases excellent assembly food), parties, getting chewed out for underage drinking etc.
However, there are the hard-core fanatics who are in the organization for power, glory, privilege, platform time. These are the ass holes. They are basically authoritarian personalities that are closed minded and have never had an orginal thought - never taken a risk in their entire lives.
The vast majority of members and leaders alike subscribe to the basic teachings but they diverge on what they find rewarding.
Those who are in for social reasons will leave when they develop more interesting social options.
Those who are in for power will leave when they lose out in a power struggle. You will see some of these on this site trying to bully and push others around as if they were still King Elders.