I have tried to argue that these abstract image representations are often better than realistic ones. But a more persuasive argument is the simple fact that they are more widely used. Images like the ones shown here are everywhere: textbooks, newspapers, journals, notebooks, the internet, etc.
But our tools for making such images are not good enough.
The best images are manually produced by artists using drawing programs. As a result, the process of creating good images is time-consuming. Even the simplest visualizations can take hours or days to design by hand. In many cases the artists find the tools frustrating and constraining.
Because of the high cost of labor, it is not possible for skillful artists to directly create many of the images we view everyday. More and more, the images we see are produced by computers.
As a result, the quality of the visual materials is getting worse and worse.
Hence, in an era of ubiquitous imagery, images are thus much less useful than they could be.