Org-mode itself is an Emacs addon, so it's not surprising that you cannot run it without Emacs. Emacs and org-mode are much more stable and much less likely to die than any other software, and that's precisely why I'm using them for a decade already.

The org-mode file format is plaintext, just like Markdown, and you definitely can edit and view it with any text editor. You will obviously lose the convenience of org-mode, though. Additionally, it's simple enough that you can easily implement a parser/importer for any other software.