I started my newsletter because I recognized I was constantly thinking/analyzing a specific topic, but not really doing much with that knowledge, and could not find an existing community focused on that topic. I started writing to put into words what I was thinking, and found I really enjoyed writing with an audience in mind, even though I had none.

If someone signs up for a newsletter of yours, that is pitched as some sort of original writing, there's a very high chance they're going to read it. If they stop reading, or unsubscribe, you can ask them why, and get valuable feedback so you can improve your writing. You end up with someone interested, or feedback. I see it as a win win.

The bigger problem is finding the hypothetical audience!

Slightly OT, but I often ask people I know, when they're struggling with things like this, "Do you want to be an <x>, or do you want to have been an <x>?", because they're two completely different things.

Me to. I wonder why that is, though. Is it the fact that I have little time? Is it my email client's user interface where an entire folder of unread newsletter emails always looks particularly intimidating? Or maybe I'm just associating unread emails with yet-to-do tasks and, thus, with stress?

I think, (for me) it might be the latter two points. I mean, I listen to podcasts on Spotify, too, and am able to make time for them. But with the Spotify UI I never get the feeling that I have to listen to each podcast or that I have unfinished business to take care of. I can listen to a couple podcasts in a row and then not touch that podcast for a couple months and Spotify won't nag me about it.