We use the PDF output to share our captivate files with learners out of our company. Planning for the end of 2020 does anyone know or have a plan on how to share these files? These users can not currently access our LMS.
Your other publishing options are either HTML5 or MP4 (video). Either way your users are going to need access to the web in order to view either type of content. Video files won't be interactive, but HTML5 would be. However, HTML5 isn't downloaded as a single file, it's a collection of files that is meant to be viewed FROM the web by accessing the server.
So, although you might be able to upload MP4 videos of your courses to a file-sharing service so that users can access them, the better option if you need interactivity is always going to be HTML5.
So far Adobe has not announced any plans to provide other alternatives that would be directly equivalent to either a multimedia PDF or an EXE format. Welcome to the world without Flash.