OK, I'm following you, but I think this is still conflating other design elements with being player-facing.
I have already effectively noted that this is not necessary to be player-facing, and that not all player facing systems have this structure, so I am very clearly NOT conflating the two.
However, removing the GM-element loops is pretty common in player-facing systems, because it is one way to serve the needs/goals of player-facing play.
If you resolve a combat scene with a single contested roll, as in (for example) QuestWorlds, that's fewer loops than if you take 5 or (gods save us) 10 rounds of combat to resolve a combat in a completely player-facing game like Dungeon World.
Sure. But "resolve an entire scene in a single contested roll" is an edge case, a specific, extremely simple, cherry-picked example. It is not the general operation of most systems in our experiences, is it?
So, when we consider design elements and practical effects, that's not a great point of comparison.