I think the confusion is caused by your formulation of this part:
Quote Originally Posted by Max_Killjoy
Those things are also fantastic from the POV of the fictional reality; that is, they're something special and reserved for a handful of "special" persons.
The underlined part doesn't really follow - a piece of technology or some achievement can be limited to a small subset of people, even one person, even if no-one in the setting thinks anything fantastic is going on. The word special refers to rarity, not necessarily impossibility.

So Tony Stark totally is doing things impossible in our reality, he's totally non-magical from the perpective of his reality, and his technology is totally reserved to him and few other genius inventors with deep wallets. But that last part is a manifestation of Clarke's Third Law: if someone in Stark's setting thinks his technology is fantastic, it's because Stark's tech is so far ahead the curve as to seem so from the perspective of the observer. Not because it's supernatural.