The mainstream history of philosophy contains people who were chosen to be represented in its history. These people did not become famous solely out of their own merits although some of them are great philosophers. People were determined to be famous for future generations. There are many more thinkers who were at least as great as the famous philosophers who are much less well known. The history of Philosophy is set to include certain figures who were lucky enough to be picked to be part of that history. People alive today who are not good philosophers but are considered good philosophers today will be forgotten by future generations. These people get certain privileges while they are alive including professorships and attention. The history of philosophy includes these very small intellectual circles of people lucky enough to be part of them and thus is deficient and partial in this way. It is true that many great thinkers are not recognized during their life while other thinkers who are unintelligent and get professorships while they are alive are recognized during their life. Great thinkers who are not recognized during their time should leave something of their ideas behind whether in writing or in art. Some will recognize them for what they are.
The partiality of the history of Philosophy is true of other aspects of History. For example, the history of America is rather the history of European Settlement in America. History is written by the victor and the whole of U.S. history contains the history of Europeans and their posterity who settled in America. There is only a very small history of the natives who settled in America tens of thousands of years before the European settlers came. Western or European Philosophy dominates the history of Philosophy in the West which means the United States and Europe.