I'm inclined to say that Cary's spot-on ... I CAN recall when email was interesting or even fun. Those days are well over a decade behind me now. When I have a question or problem or exciting thing to share, I'm more likely to pick a targeted forum (e.g. pymarc mailing list) or faster-moving one (e.g. Twitter/C4L Slack/Discord/ etc). Most listservs I'm still on I only receive as digests and I skim the subject to see if there's anything interesting.
I think there's also a size/opt-in component -- how many hundred people am I emailing? do they all want this individual email? (I take some comfort in the digest--but that option hampers conversation) The email is being shoved into everyone's inbox and there's no "opt in to only what Ruth and Tim say but not what Kyle and Eric say" so keeping up with an active mailing list can significantly take over one's day.
Whereas I opt into whom I follow on social media--and know people can opt into following me or block me easily (except on Slack) if they aren't interested in "Ruth's thoughts on X,Y,Z." Opening a social channel is a volitional act/tagging everyone in a Slack/Discord/Teams had better be important, whereas this is like a memo that is appearing in everyone's box along with tons of other unwanted things and a few important things.
With so many ways for things to get at us during the day, I tend to feel the happiest when I've got my email/slack/teams closed and my "Forest" browser app on so I can't go to social media.