No. It's relevant to norms and values. Explicit or implicit. And thus, to morals.
Okay, sure.
What are the "values" of how the Epstein drive works in The Expanse?
What are the "morals" of Roshar's geography in Stormlight?
OK. Well that's just factually wrong.
Fine, okay, if we go by the absolute literal definition of theme, then yes, there's no relationship between theme and level of sophistication.
You realize, of course, that by the letter of the definition, then practically every single story ever created has a theme to it then?
It's not relevant to whether or not they have one. But that's precisely my point. You were the one who seemed to be implying that simple or non-moral stories don't have 'themes'
Simple stories can have themes, yes.
The Triforce literally does reinforce the theme of the tetrad of Power, Wisdom, Courage in LoZ. Its actually one of the clearest and most widely known examples of symbology used to reinforce a theme.
The symbol came before the symbology, and not every LoZ game has referenced the tetrad.
The Triforce started out as McGuffins - it was a recurring icon in the series long before meaning was attached to it.
Why add "deeper" there?
The guy's death served a narrative purpose. That's an idea.
Character deaths in fiction are "ideas."
...sure, whatever. If you see this as a theme, then there's no point debating it.
Yes, every such work would indeed have a theme of conflict.
It's good to know that something like Modern Warfare 3 has a "theme" simply by virtue of it depicting conflict between countries. 0_0
You seem to have this bizarre idea that to be a "theme", a concept must be elevated, mega important, deep. That's just not the case, and I'm not terribly sure why you'd think it would be.
"If everything is X, then nothing is X."
Or to be more succinct, if a theme isn't developed, then what's the point? There's a reason why in all levels of education that certain texts are assigned and not others. If I'm doing a course on war literature for instance, chances are I'm going to come across something like Dulce et Decorum est, and not Call of Duty.
Plus, even on the personal level, it would also mean that I could create an absolute piece of crap and say it has a "theme" by virtue of it having a conflict between two parties. People would rightfully laugh, and they'd still be right to laugh even if I pulled a "technically" by the literal definition of a theme.
A bunch of people liking a horror movie doesn't make it not a horror movie. That's a stupid way of classification, like: "Hey John, a bunch of people liked your horror movie so we need to call it something other than a horror movie", "Sorry Daniel, your thriller sucked so it's just a horror movie"
A movie doesn't stop being a type of movie based on how it's appreciated. Genre isn't related to quality. But what horror films may or may not be considered literary is something I'd generally rely on critical consensus to ascertain.