The auteur is suspicious of language.
The assumption behind every collaborative creative endeavor is that language can capture ideas, and that language can mediate between ideas. Those who believe creative collaboration is possible believe that multiple creatives can enter the same room, use language to successfully communicate their ideas, use language to successfully mediate between their ideas, and use language to combine their ideas into a worthwhile final product.
The auteur believes otherwise. Language, he says, cannot communicate an idea without botching it. And if communicating an idea were not bad enough, mediating between multiple ideas using as flawed a tool as language is immeasurably worse.
Neither perspective is completely correct. The reality is that there is a tradeoff between the approach of creative collaboration and the approach of an auteur. What creative collaborators gain through specialization and the combination of talents, they lose in the fidelity of their ideas' expression; what the auteur loses through not being able to harness others' talents, he gains through the ability to express an idea to its fullest. Naturally, the more talents the auteur is able to accrue, the less he needs others, and the more worthwhile the tradeoff of solo work becomes.
Reflections and originals
There is a short story by Borges, about an author who realizes on his deathbed that the words used to describe a rose are not a mere reflection of an object, but an object in their own right.
"Marino saw the rose, as Adam had seen it in Paradise, and he realized that it lay within its own eternity, not within his words, and that we might speak about the rose, allude to it, but never truly express it, and that the tall haughty volumes that made a golden dimness in the corner of his room were not (as his vanity had dreamed them) a mirror of the world, but just another thing added to the world's contents."
The auteur believes something similar about ideas. A description of an idea is never the idea itself, it is a second rate copy of an original - another thing added to the world's contents. Preferring not to clutter the world with such refuse, he becomes reclusive, reluctant to even speak of what he wishes to create. The result is either pure creativity untarnished by the translation of ideas into words, or something tantamount to the work of a madman - full of meaning to its creator but incomprehensible and useless to everyone else.
Anyone doing creative work must carefully toe the line between two extremes: the collaborative extreme of butchering ideas by putting them into words, the auteur's extreme of refusing to communicate anything about an idea at all.