> In point of fact this is actually an argument IN FAVOR of Obsidian. While the editor might be proprietary - the notes themselves are just standard markdown. If somehow all the copies of Obsidian magically disappeared off the earth tomorrow, I could easily switch over to Emacs org mode, VS Code, or literally anything else.

100% this. The reason I started using Obsidian in the first place is that it's built on the exact directory structure and file formats that I was already using to manage my writing and notes, and if Obsidian goes away for some reason, that won't change.