Because there's no point on complaining about a complete game, nothing will be changed.
But in this case with enough complaints he may see the light and add CGs.
here is a quote from the creator's patreon
"Q- Are you planning on adding pictures to the game as well?
A- Yes, as the game continues to develop and increase with characters etc, eventually I'll release a build that remasters the entire game with actual character art and things during the scene.
but that update won't come for awhile. "
so before people start complaining about this, they should actually look