I used a "Tell HN", but mine from 11 years ago is still going strong. :)

https://news.ycombinator.com/item?id=1494362

That said, I think most of them die because of a lack of time and/or other interests come along. I can't even count how many folks have reached out about starting a similar newsletter and only one or two kept going for more than year. With side-project especially, it is hard to find users, and that can be pretty discouraging.