I don't have a Medium account so I'm not sure if this is still true, but there was once a button in the settings to export your content as a zipball. If you'd like to migrate to a self-hosted blog, I wrote a tool which will convert this zipball into a Jekyll blog:
That's pretty nice. For people looking for an alternative with the same convenience as Medium, converting the archive of Medium posts to a GitHub Pages site could be a decent solution.
https://git.sr.ht/~sircmpwn/unmediumify
If you want, shoot me an email for free hosting, and I'll rig up builds.sr.ht to automate deployment for you, too: sir@cmpwn.com