1. Lots of self-hostable solutions are available.
2. Unfortunately for mailing lists, those self-hostable solutions very often make it way easier to plow through conversations.
3. Out of sheer curiosity - have you ever had an actual e-mail conversation with multiple persons involved in replying to each other's e-mails? I do it daily and it sucks.
If you know of something which is easy to set up, easy to administer, easy to use and provides better handling of multi-way threaded discussion, I'd be interested to hear about it.
(I know Python is experimenting with a forum-based solution, but I worry about the burden of both yet another account to create and site to check, and finding people to maintain and moderate it)
it's very easy to write an email and there are some benefits to it. I.e, you don't need an account on a proprietary (Microsoft owned) system.