Most blame is misdirected, for people are usually doing the best they can in the system they are in. It is the structure of the system, not the effort of the people in it, that determines the outcome. The way to gain more influence is to understand the structure of the system. Systems thinking is an essential tool in helping you to manage yourself and others more effectively. In business, it will help you understand the complexity of a process so you can see how to improve it.
Systems thinking also helps with teams and team building, because teams act as a system.
First, because it has tended to be used mostly in technical and mathematical pursuits, and so confined to academia. It is only recently that the ideas have become available to a wider audience. School and university curricula are drawn up to last for years and they take years to complete. So there is always a delay between what is current in society and what is in the school syllabus. Systems thinking is just beginning to be taught in some schools.