I'm wondering if building "social" around each edition of your newletter could make it more engaging and sticky. This would be something like Imgur where a community with engagement and commentary forms around each image/album except for newsletters.
How it could potentially work -
Right now, this is somewhat achieved using HackerNews or Reddit where people post their content and hope that discussions form around it.
What does the group think?
Dru from trends.vc uses circle.so to bring in a community around his work. I don't personally use it, but might be interesting to consider as a way to build an insular community
As for commenting and discussions, worth taking a look at this: https://minimaxir.com/2014/10/hn-comments-about-comments/
Basically the vast majority of users comment once, and there's an exponential decay. and hackernews has a lot of folks there, so it can afford to have people posting once and still have some semblance of a conversation emerge. not sure if it'll work for an individual newsletter where my hypothesis is that people who pay for that information are not looking to engage others on it. Counter-example I can think of is trends.co, where they have an active and closed FB group, but the community is the draw and they hardly ever talk about the actual articles there.
I got great value from your comment! It's making me think a bit differently about an idea I am working on and pitching to customers.
Happy to help :D
Thanks for your comment. I’ll take a look at the links you provided.