There is a definite link between user activity and the Price of Steem. Higher prices tend to induce people into a greater level of activity activity. I would agree that auto-voting does have a negative impact on engagement through comments, but also has the benefit of at least supporting a community with members whose posts you may not always see.

A good balance between the two can be difficult to find. I'm not a great commenter (if that is a word), and I'll admit that, but I also combine auto votes with manual curation, even where I don't feel I have anything to add in the comments. That is just me...