Jack, I have only been on Medium since February but it is apparent that anything more than a month or two old is basically invisible. Which is why I include a link to an older story at the bottom of my new stories. It does work occasionally. I get people clap for both the new and old stories. Some have even followed the links chain four or five stories back. It doesn’t happen a lot, but it is worth the extra two minutes work.
I haven’t “republished” anything.