I think needing to have that is, in and of itself, a sign of complexity.
I would say its more accurate that its a sign of inaccessibility and impracticality.
Its akin to wanting to have a proper joystick for a proper flight sim (ie, not arcade style like in Battlefield). These games aren't always all that complex, but they do become impractical to play with a mouse and keyboard, and only more so if the complexity actually does go up, and so the desire to have specialized equipment goes up.
Likewise in a TTRPG, having a lot of prewritten spells isn't really a complexity issue. It just isn't practical to memorize all of them, so it becomes more efficient to reference them. Cards are a more specialized tool for that than a book is.
DND style spells aren't even remotely complex compared to something like Ars or DCC.
Conflating accessibility and practicality with complexity is the wrong approach, is my point.