As an epistemological position, solipsism holds that knowledge of anything outside one’s own mind is unsure; the external world and other minds cannot be known and might not exist outside the mind. More from Wikipedia…
Solipsistic thinking is abundant in modern life.
Barack Obama, Hillary and Bill Clinton, Donald Trump, many theatrical stars, the wealthy, and those with strong egos often create their universe around themselves; and, of course, they know it best. The path is ego-centrism to solipsism.
Our television culture encourages solipsism; the story lines model it every day and have done so since the creation of the medium.
Solipsism opens the path to narcissism.