Changing one's name is not only a phenomenon of the late 19th and early 20th centuries, but it also occurs in the periods preceding and succeeding that time. I found many instances from the 17th century forward of names having been changed. In the 17th and 18th centuries, names were often spelled phonetically. So it was not unusual to find a person's name recorded differently from document to document. The phonetical spelling varied with the nationality of the person recording the event. So for example, I might find a resident of New Amsterdam recorded with a Dutch spelling of the name and that same individual as a resident of British New York with a different but similar spelling of the name.
As my family moved from New York City to other parts of the colony and to other colonies, the surnames was spelled in six if not more different ways. As people were themselves recording their name, they took on the various spellings of the name. In some cases, the individual simply gave into how others were writing his or her name. I have an Indian friend who changed his name because he got tired of people not being able to pronounce it or because when he was asked to spell it, the person just could not get it.
I have other friends who made a name change because they did not like the name that was given to them. You can find many instances in which a person chooses to use a middle name or just the initials because to that person it sounds better, more professional, or for whatever reason.