I really dislike this diagram. I think it just perpetuates a damaging stereotype about research, one that makes it harder for people trying to do (entirely valid) types of research that fall outside of the stereotype.

The stereotype is that research is about making every-more specialised contributions that extend existing work in finer and finer-grained ways.

What research falls outside of this stereotype? Synthesis. Theorising deeper foundations that connect disparate bits of knowledge and gives a deeper understanding of them.

Why is the stereotype damaging? It equates research with simply making more specialised extensions to existing research, which means that it's seen as "a good thing" for research to be sharply-focused on a very specific topic. In a slogan: narrowness good, breadth bad. Breadth is seen as lack of focus, trying to take on too much.

But breadth is not always bad. It depends on what kind of research you are doing. Breadth can actual simplify the task and make it easier, if your task is developing a deeper, underlying theory.

And if someone can develop a deeper theory, that work can have -- to relate this back to the diagram -- an impact that projects across and reshapes whole segments of the circle.