There's a fair bit of noise in those charts due to the activity of bots. An individual bot account can post and vote as many times as it has the bandwidth to do so, where a human is limited by attention. Many of those bots were shut down in recent weeks, after changes which made them less viable. It would be great if we could have "bot adjusted" charts, but I'm not sure how that would be possible.
I believe, you can see the shutdown effect in Votes chart (huge spike and drop). Still, it doesn't justify the stagnation of Steemians engagement.