Steem activity follows a lot the value of STEEM the token. Since the token dropped below $1 not as many keep up every day. But those who are consistent and probably the ones who add most value to the platform are still around in the most part. The ones who follow the price of STEEM (and trust me, it was a crowd when I joined and STEEM was still at around $5 and SBD very high also), they are the first to leave when there is trouble. They are not consistent and don't really care about Steem, only about short term earnings and profit.

As for HF20, people who join via Steemit get a decent amount of daily activity, because of the delegation. Other DApps should find some means to temporarily boost the experience of the users they attract too. At least until SMTs, when RC delegation will be possible and we would have the mechanisms to create pools for those needing a minimum of RCs.