Going by this definition of public domain, I don’t see how this could be the case:
> The public domain consists of all the creative work to which no exclusive intellectual property rights apply[0]
Think of it this way. Imagine I wrote some code, and when I ran it it generated a piece of art. Surely I would have IP rights over the artwork? Otherwise you could make the same argument about art made with a somehow automatic paintbrush I built.
I hope I’m not talking at cross-purposes here and using a completely different definition of “public domain” was was intended, apologies if this is the case.
There is a difference between the concept of a computer being a "clever pencil", which you are referring to, and the computer generating weapons and gear to generate a drop from a selection of "$ELEMENT $LEVEL $WEAPON $MODIFIER" (e.g. fiery epic hammer of orc skull crushing) which is equivalent to generating all of them (not copyrightable).
Now, the individual visual components of the weapons could have a copyright but the computationally assemblaged work based on the components would not because they've just run a job to "generate all the permutations".
For something like No Man's Sky, which is extremely procedurally generated I reckon it's very grey and they could try to make a case but the actual world they generated for people to play in would not be protected by copright. I don't think it's well tested in court.
In the case of the monkeys the hat, the basemonkey, and sunglasses could have a copyright but the assembled monkeys generated by a computer with no creativity would not. But it's a derivative work of things with copyright so that aspect becomes super grey.
As you say, it seems like there’s a significant grey area that needs to be resolved, and I could see it being quite difficult to figure out where to draw the line in practice.
It does mean that.