At least where SN doesn't need to do something, I'm more interested in incentivizing stackers to do it. It's less obvious how this should work, and is harder to pull off, but I think such a solution would solve the problem more sustainably.
It requires answering questions like:
  1. what would encourage people more likely to share posts/comments from SN on other social media sites?
  2. what would encourage people to invite their friends here?
  3. what would encourage people to participate here more?
These are questions we'll need great answers to if we want to grow autonomously.