Ovinomancer
No flips for you!
Spells step very far outside the realm of most other character abilities in that many create entirely new situations. Instead of fireball, take Banishment, or Illusion spells, or Charm Person. These radically alter the fictional situation and some force continued narration according to the binding resolution on the GM.I'm not sure spells are all that special of a case, compared to any other character ability.
The player decides what the character's choices are (they choose to cast fireball) - the dm decides what that means in the narrative. If it's an anti-magic zone, it means one thing, in a dry forest it means something else... but the dm has final say. The player can't tell the dm that the anti-magic zone isn't there, and that the description in the PHB is to be followed regardless of the fiction. The player has control over the decision (the dm can't tell you what spell you cast), but the results of the act of casting are technically/ultimately under the dm's authority.
But unless there's a reason otherwise, the character's decision to cast fireball, presuming that's a thing the character knows how to do, should almost always result in a ball of fire, at least. Technically the dm can say no, although most of us would expect that a dm who say no to your spell has a good reason for that.
But it's also true that the original breakdown of the play loop left out an important point in step 3: this decision (by the dm) is assumed to follow the agreed-upon rules for that table, whether that means RAW or something else. It's kind of a big thing to gloss over, methinks.
At least, that's how I've always played DnD.
The points about anit-magic zones are still rule-0 Force but by more roundabout means. Here the GM is imposing Force through prep decisions rather than in-resolution decisions. This can be better, and even move away from Force, if there's a fictional reason that facing the players and a way to manipulate this available to the players. Most of my experience with anti-magic is just the GM shutting down magic, usually for plot reasons, because otherwise the narrative control that spells allow can derail prep. The reality is that the GM has to be obvious about using Force if they are disallowing spells to function. I'm on record that Force isn't inherently bad, and good play most certainly exists alongside it (else all published adventures would fail), I'm just being explicit about the fact the any ruling disallowing or altering spell resolutions is obvious GM Force. Doesn't mean it's bad.