You may or may not have noticed this.
There's a vaguely interesting recurring element of the artwork of small children: perspective tends to be based not on size or on distance, but rather is weighted according to importance. The canonical example would be a child drawing themself standing next to a huge, mammoth flower that towers over their head.
This object is important. Therefore it is big. Look at the child; look at the flower. The flower is more important. The flower is what i want your attention drawn to, therefore it is more visible. Look at the flower more than you look at the child.
Simplicity is not a bad thing here; all that matters is expression. In the mind of the child, all that is important is that the thing is expressed, that it gets down on paper. The ideas of formalism, that things must be drawn this way, that we are meant to make a carbon copy of reality, has not yet been embedded into them; all that matters is the flower and the child. And to some extent, this works better than anything else could; the picture in the end may not convey reality, but it conveys exactly what was in the child's mind.
The really interesting bit is that this isn't necessarily limited to children. Some of the really early medieval painters did the exact same thing, working from the same base starting point-- lacking any formalism or anything to build on, starting from scratch to communicate something, ignoring the medium and concentrating on nothing but symbols. So you'll see some of those early artworks, done by full-grown men, learned monks, that have a huge Virgin Mary and a relatively even larger baby Jesus, and the people around barely up to Mary's knee. Or that have certain apostles twice the size of the others based on which they think was more important. And it works.
So the thing i've always wondered is, were the painters aware at the time that they were doing things that way?