Nice article on the subject,

The main problem I see with the fact that nearly all the voting power comes from Curation groups is that it provides zero incentive for users to buy and power up Hive. One of the things I always liked about Hive is that it's was possible to meet like-minded people and actually give or receive an upvote that is worth something which feels nice on both ends.

Now, many are just hunting for curation group upvotes bringing specific content. it looks like Splinterlands stopped providing their weekly challenges which I'm quite sure made the number of posts on it collapse.

Imo curation groups, or Hive at its core should have some kind of requirements in that users need to have a minimum amount of Hive Power to be curated. Just so many are using Hive as a cash cow, withdrawing everything they earn from big upvotes they systematically are getting. This is what has been killing Hive.