People are powering down because the dev team hasn't "released" JACK for a while. The sign up process still is not fixed and people searching for an alternative to facebook can't join in unless you pay a fee for an account. The cultural expectation is that social media is free. Steemit can't change that and will fail if they try. Other blockchain social media projects are coming into the playground and since steemit doesn't seem to take the competition with facebook seriously, people are powering down and hedging their bets.

Facebook is going to fall to a blockchain competitor. That is set in stone...but will it be on the Steem blockchain? That remains to be seen.