The vast majority of the world's books, music, films, television and art, you will never see. It's just numbers.
Consider books alone. Let's say you read two a week, and sometimes you take on a long one that takes you a whole week. That's quite a brisk pace for the average person. That lets you finish, let's say, 100 books a year. If we assume you start now, and you're 15, and you are willing to continue at this pace until you're 80. That's 6,500 books, which really sounds like a lot.
Let's do you another favor: Let's further assume you limit yourself to books from the last, say, 250 years. Nothing before 1761. This cuts out giant, enormous swaths of literature, of course, but we'll assume you're willing to write off thousands of years of writing in an effort to be reasonably well-read.
Of course, by the time you're 80, there will be 65 more years of new books, so by then, you're dealing with 315 years of books, which allows you to read about 20 books from each year. You'll have to break down your 20 books each year between fiction and nonfiction – you have to cover history, philosophy, essays, diaries, science, religion, science fiction, westerns, political theory ... I hope you weren't planning to go out very much.
You can hit the highlights, and you can specialize enough to become knowledgeable in some things, but most of what's out there, you'll have to ignore. (Don't forget books not written in English! Don't forget to learn all the other languages!)
This in an excerpt from NPR's Blog. You can read the whole article here.
Holmes, Linda. The Sad, Beautiful Fact that We’re All Going to Miss Almost Everything. NPR Blog, Culture and Criticism. April 18, 2011.