Carl Sagan Vs. The Cthulhu Mythos?

[Coidzor]

...predictably, no. There are settings where magic refuses to play by formulaic rules and has a Fairy Tale-like behavior. And most such 'wild magic' settings indeed are more low-magic, portraying magic as this thing beyond the grasp of mere mortals.

It's one of the oldest fantasy tropes; one D&D and games like it infact are defying.

This is not the same as "truly random" however, as there'd be no way to work out a system of how to begin "practicing" magic.