Ehhhhhh. I don't think anyone expects to be setting up their Plex server with an Internet outage. As long as you have been setup prior and you lose Internet you can still log in with the last local profile you used. It's not perfect but you're not locked out. No workaround (at this point in time) is necessary, assuming you've already authed and added your server to your "whatever" device.

And ultimately you just keep Kodi for the apocalypse. This complaint about "not being able to access your media" if the internet is out is misleading. Of course you can access your media if the internet is out, it just might not necessarily be with Plex which is ultimately an online service. Sure we can call it a limitation but that's just nit-picking since most everyone has their Internet up almost all the time, offline does work, and there's plenty of other ways to access your media.