A 90% churn rate doesn't portend a much longer period for data to accumulate.
I've been here long enough to have learned many reasons for leaving, and had my purpose in coming here been to earn, I'd have been gone.
The simple fact is that most people are attracted to Steemit by the potential to earn. When they observe that Steem is being concentrated at an ever increasing rate into those accounts with the most of it now, they leave.
They don't even need to get all they way to that truth. They only need to see they can't get a fair shake. Slow learners, those willing to descend to pandering, buying votes, etc., take longer than most to leave, but they usually go too.
Some few stick, mostly because they're not here for earnings, like me.
No one is averse to earnings, however, and there is a collective breath held, awaiting a platform that actually performs what Steemit advertises.