I agree the issue is most DM's never get any real education on how to do it. Dragon magazine and others used to fill that void, for awhile the RPGA society was good for teaching stuff like that but Organized play morphed into a weekly dungeon crawl thing that doesn't really require anything but a body to read the captions to the players and adjudicate the dice.This doesn't seem right to me.
I work closely with many students. All aspire to be good writers/thinkers. But many of them just don't know how. I teach them principles. These can address general issues of text structure, such as where and how to use headings (students who are still learning tend to place their headings either too early, so the first paragraph under the heading actually deals with the previous topic, or too late, so that the topic is introduced before we get to the heading), or detailed issues of sentence structure (eg students have a tendency to bury important assertions inside subordinate clauses in long sentences, which makes their key ideas and arguments hard to extract).
These students are bad writers and arguers, in the sense that their writing and arguments need to improve. But bad writer is not some sort of essential or inevitable category. By learning and practising in accordance with certain principles, they can (and in my experience they do) get better.
It's not a "people problem". It's a skills and techniques problem.
Likewise for GMing. If a GM is running a railroad, but doesn't want to, how does s/he change? Part of that is introducing him/her to new principles. And I don't mean principles of little practical applicability, like don't railroad! I mean much more concrete principles like Here's how you should frame a scene or Here's how to avoid the game bogging down in endless retries - Let it Ride! or Here's how to handle failure without your game grinding to a halt - focus on intent moreso than on task. Etc.
I've learned many principles and techniques from reading good RPGs and good RPG commentary. I've adapted them to the play of games that don't themselves feature them at all (eg Rolemaster) or terribly clearly (1977 Classic Traveller) or as consistently as one might desire (4e D&D).
I've got no reason to think I'm unique or even terribly atypical in this capability.
Or in other words, this.
Hopefully the videos and stuff Available online these days help out players but I think the RPG game companies have always hobbled themselves not having more online resources for DMs