Ovinomancer
No flips for you!
Oh, my. I certainly seem to have a different experience than you do.And I claim that every GM does this. Some may do it more, some may do it less, but it is impossible to not do it at all. So at most it is a continuum, not a binary.
Let's break this down, though. Let's start with Gloomhaven, which is widely held to be a very RPG adjacent boardgame. It's not an RPG, but it's rather close. In Gloomhaven, it is impossible to have story curation -- the game is entirely driven by mechanics in resolution. I think we can all agree that the primary focus of a game like Gloomhaven is skilled play.
Now, let's shift a bit into an actual RPG. Let's look at B/X. I can absolutely set up a dungeon very much like a Gloomhaven one -- three to five rooms, combat challenges, puzzle goals. I can then run this for players in a very much "this is what's here" way using the rules strictly and never once introducing or altering a thing -- ie, without curating story at all. The only "story" here is what happens in play. But, this is very simple, a simple dungeon, straightforward encounters, not terribly complicated. However, it's still an RPG, clearly, and run without any story curation, and, I can absolutely scale it up to much more complicated dungeons and still hold to this process.
What I think you're talking about is running a much more modern game, where story is an important factor, and so you'll probably discount the above, maybe as not a real RPG. But, it is, it's what a hard skilled play approach looks like. There was a poster here, who I haven't seen for a bit, that made elaborate set piece 3-D dungeons. They were gorgeous. And he talked about his play as pretty much nothing but hard-core combat challenges strung along a loose storyline. That was absolutely hard-core skilled play, and he was raked for it. It didn't help that he was aggressive about it, though. But the point is that such games can absolutely exist. And, if you're like most modern players of 5e, it seems alien in concept because story curation is very much the norm these days. Skilled play isn't something well supported by either the ruleset or the general zeitgeist around 5e. Which is perfectly fine. But refusing to see that it can even exist? That's a bit much.
Which is very much story curation and not skilled play.Again, not necessarily. You can just make a best possible 'story' with the elements you happen to end up with.