As for extracting meaningful info with other editors, I would say it depends on how you structure your notes. For me it's just a very long bullet list with some tags here and there. So a plain text editor will only 'add' some star characters at the beginning of each lines, which appears quite readable to my eyes.
Obviously you won't be able to execute code blocks, reformat tables, follow links, fold sections etc.. but everything is just a search away..
That’s not what that means.
I take your point in it being bound to Emacs however. Pandoc is an excellent tool for conversion though, and other editors are catching up quickly.
Note: I don't know what raw orgmode files look like, maybe they're similar to Markdown.
The thing is, Org format is defined by the way Org-mode in Emacs handles it. Beyond Markdown-like features (which are rather easy to parse out; the format is similar), you get things in the data format that to date are handled only by Emacs. Think of Emacs + org mode as a better Jupyter notebooks than just editor for static text documents.
Consider this note I have in my org file for work tasks.
** DONE [#A] Testing prior to syncup meeting :CUSTOMER_development:
CLOSED: [2018-07-13 Fri 14:04]
:LOGBOOK:
CLOCK: [2018-07-13 Fri 12:14]--[2018-07-13 Fri 14:04] => 1:50
:END:
- [X] Baseline test for REDACTED
- REDACTED NOTE
- [X] Baseline test for SOMETHING ELSE
In this sense, org format is both a nice Markdown alternative, and - when coupled with Emacs - enables very powerful interactive documents that can handle task management, time clocking, literate programming, spreadsheeting, and other tasks.
I suspect Org will never be as popular as Markdown simply because, if you wanted to go beyond Markdown feature parity, you'd have to reimplement half of Emacs to handle those "advanced" aspects.
With Markdown I can use any editor from a full-featured IDE all the way down to `cat` or `ed` and all I'm giving up are some quality of life features. It's the same format at the bottom, and it has the added benefit of being ubiquitous in that nearly every editor has some basic Markdown support. I can write it anywhere and take it anywhere, not so for Org-Mode.
I think I prefer the Markdown approach of keeping the file format light and plain, and building the quality of life features on top in the editor.
As for your orgmode example, it's not a very good example of "just plaintext" if the metadata code in between the bits of text is larger than the content of the note. I imagine that with nice syntax highlighting it becomes easier to parse in just a glance, but then it's no longer "just plaintext" in the same way that e.g. YAML isn't.
It probably works very well, but to me it looks a lot like a plaintext encoding of a database record or something. It's a different use case. Not a simple note that is "basically plaintext". For instance I would not feel entirely comfortable editing your example without worrying I'd mess up the structure or produce a syntax error. Though maybe the format is really forgiving, I can't tell. What happens if you forget the :END: bit, for instance?
Of course you can read Orgmode in plain text, because that’s all it is. Maybe you looked at a file with a bunch of meta-data, or a file with a bunch of code blocks, but so what? Ignore the meta-data and just read the notes. They are all delimited by asterisks by their header level. Links are simple. Tables are simple, even tables with formulas are readable.
Further more Markdown is a poorly defined plaintext format, which is why there are so many variants of it, and processors specific to those variants. If you don’t believe me, remember that GFM is not official markdown.
Orgmode is at least well defined, so when other editors catch up and are able to implement all the features Emacs has when using it, they should behave similarly. If you want a well defined plain text format that exports to HTML/PDF/Word/RichText take a look at AsciiDoc or reStructuredText.
But don’t blame Emacs for leveraging its power over a relatively simple plain text format. There are even packages these days for Vim, Sublime, Atom, Jetbrains to make good use of Orgmode without Emacs.
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.