Maybe there is something about the tone-mapping too, I don't know, I can't say that I studied that too much, but in my eyes, I constantly see the shaders as a problem. And who can blame the artists ? Choosing the parameters for shaders is completely arbitrary.
I would say if a renderer would implement a great tone-mapping, it could help more for realism, because a tone-mapping would be largely automatic. While the shaders would continue to leave lots of room for errors, because they will continue to rely on the user tweaking lots of parameters.
And in the images you posted I also see another constant problem which hinders realism. The world is far too perfect. Every line is impossibly straight, all the bricks are symmetric and identical down to the millimeter or even atom. Most surfaces are perfectly clean and uniform.
So to recap, I think these weigh heavily when it comes to realism:
- shaders
- the world is too clean and perfect
Even when it comes to "dirty" worlds, or nature or for example forest grounds things can look off, because again the user needs to make lots of decisions. The scale of the leafs and stones, scale of the bump map or displacement, reflectivity and glossiness of things and so on and on.
A good painter, or someone with a good eye would get better results in these cases.
I remember seeing a vfx reel for The Spiderwick Chronicles and they rendered with a low quality renderer with Vue, and as far as I know they also used low poly, low quality trees, and the images still looked photorealistic.