We have consistently overestimated what computation is capable of throughout history, whether computation was seen as an algorithmic method executed by humans, or a process of automated deduction realised by a machine. The fictional record is crystal clear on this point.
Instead of imagining machines that can do a task better than we can, we imagine machines that can do it in the best possible way. When we ask why, the answer is invariably some variant upon: it is a machine and therefore must be infallible.
This is absurd enough in certain specific cases: what could a ‘best possible poem’ even be? There is no well-ordering of all possible poems, only ever a complex partial order whose rankings unravel as the many purposes of poetry diverge from one another.
However, the deep, and seemingly coherent computational illusion is that there is not just a best solution to every problem, but that there is a best way of finding such bests in every circumstance. This implicitly equates true AGI with the Godhead.