"org-mode developers, in turn, just ask a relevant big question: 'why use separate files when you can conveniently stick the stuff in one file, dammit?'"

It surprises me that you could come away from org-mode thinking that the developers thought you should stick everything in one file. One of the main strengths of org-mode is the way it frees you to put stuff into separate files, wherever you want, and then use the agenda to consolidate them into a single view.

Having said that, yes, org-mode is freaking awesome.