I think a lot of it is just down to money/vote power. I am one of those that will occasionally upvote a random comment I read, (used to happen more in the past due to steem price), but now it becomes a thing of trying to maintain a balance. Prices are down so we have to adjust. Post that have payouts get 505 vote so I can give at least a slightly above dust level vote on comments. So that with prices down that means less votes available.
I think another thing other than a loss of potential votes is that of the comment flaggers, someone new comes in to steemit very limited on SP and RC powers. They make a mistake, by asking for a follow, someone not even the Post Author in most cases flags the comment with no concern for the effect it has on that person to interact on steemit, thus shutting out a potential commenter.
Any one that has stopped comment because they think they should be rewarded for the comment needs to reassess the current realities of the price of steem, and their own actions when commenting. I am happy to say that it has been at least 8 months since I have seen terms lie 'What good enough for a comment but not a vote" from post authors. Those types of comments do not lead to engagement at all.
As was pointed out also by I think @kabir88 a lot of post lately do nothing to raise the engagement level. When I receive a comment If the comment requires a reply, I try to reply. Not all comments need a reply. I do try to give a vote to most of the first level comments on my post, that however does not include blatant vote farmers, those that leave a comment and obviously did a copy paste comment or did not really read the post. I do look at the blog of those that leave a comment to ascertain this, it does not take long, and often I find a post or two to read and then comment on one of theirs.
There are not a lot of cases where a comment should be flagged. It would be nice if steemit had a way of flagging the voter not the content creator, that way comments that have been unduly upvoted can have the votes nullified without damage to the commenter/content creators reputation.
Educate the "I vote for you you vote for me" type people. School them that it is a wrong comment to make. People can say all they want about new users doing research to learn the correct etiquette, not an easy thing to find on steemit or other blockchain places. (I am having that particular issue with trybe and whaleshares).
We all have expectations, but no one knows what those expectations are until someone tells them what they are.
The only part of people being careful and afraid of speaking their minds are the small minded people that attack them for speaking their mind. Not everyone can ignore the ignorant attacker. I have had a few of my comments attacked, but at the same time I have also had people point out where I was in error. the attacks often come after the solid explanations of where my reasoning went wrong. But there is very little a person can do when the attacker upvotes themself to make it appear their comment was made first. We don't always look at the time lines.
So let's get the dev-team to lower the RC cost of comments like they lowered the cost for Votes, and maybe commenting will pick up again.
Trybe and whaleshares @bashadow, can't believe you've been cheating on us :P
Trybe is down, I guess it got hacked, but did not work today. I have no idea how to use it, just joined for the free tokens coins they give when you log in on a daily basis, but I forget to do that a lot. As for whaleshares, I think half or mor of the top 20 steem witnesses are witnesses on there. So far not sure what I am doing there either, heck I don't know what I am doing here, other than it is not facebook, or twitter or youtube is the pee ode people at reddit. The meaning of Social online has changed a lot in the almost 20 years I was gone fro it all.