alt Hacker NewsI am saying that if you have an outlet where your posts are getting 10 to 20 thousand impressions, the most impressions out of any other channel of communication you should not abandon it.
Being on social media is very relevant due to both content discovery algorithms being able to connect people who may be interested in the project with the project itself and because social media sites can have things go viral outside of your own personal reach. Your post can reposted or spread by other accounts easier if its originating from the platform itself instead of hopping someone sees it and copies onto the platform.
Mindshare matters, too. A big reason why small distros manage to get a foothold is because they're highly visible in places that get traffic (which then kicks off a virtuous cycle further increasing visibility). When existing Linux users get an itch to try a different distro, the ones that will come to mind to try are those they saw on reddit/youtube/xitter/etc, and Linux newbies are also going to be inclined towards these high visibility distros.
Holing up in mailing lists definitely isn't going to help with pulling in users or devs.