I respectfully disagree. Sure, one is not dumb by going to what's serving one's needs best. That being said, the cool idea, as you state it, is IMO quite workable. It all depends on ho capable your text editing environment is, I guess.I wasn't talking about Markdown. I was talking about keeping an entire GTD system in one text file. It's a cool idea but it just isn't functional.
For example you could 'tag' every line in your textfile:
get Harry's feedback on cost/benefit analysis @calls
Then you could grep that file for "@calls" to get a that @calls list as your output.
Likewise a calendar would be do-able:
20-03-28 reply to Peter on GTD board @computer @calendar
Again, have a grep at those "@calendar" lines, maybe have them even sorted by date (alphanumerical).
You could have your text-editor sort those lines for you, of course not, if you use Windows Notepad.
But, really, all you need is a text editor and the CLI and then you can accuse Org-mode users of using over-engineered and bloated software just to get organized