Oh no, people have to consider how they engage with others’ writing! They can’t just push a “like” or “thumbs down” button! There will be social pressure against it if they try to just send around picture or video memes instead of writing something thoughtful! And worst, everyone gets to be in control of their “experience of the same message,” by using the mail client that works best for them!
All of the reasons you say mailing lists are, let’s say, “dated” are actually benefits of using them, especially when using them for engineering purposes.
I agree that the available features can steer the online community culture and behaviors, but it's not determinative. I don't see why online communities should give up useful features just because other communities use them in a way you don't like.
I've been using mailing lists for about 30 years now. In the days before social networks, there was tons of forwarded crap and email chains, such that debunking them was a cottage industry. This behavior eventually moved to Facebook and Twitter which is perhaps why email lists seem more civilized these days, but I don't believe its the features that are driving it.
All of the reasons you say mailing lists are, let’s say, “dated” are actually benefits of using them, especially when using them for engineering purposes.