Answer: Well, your question starts off with an incorrect assumption.
Self publishing does work. It’s worked for hundreds and hundreds of years. Poor Richard’s Almanack was certainly a success – it was printed starting in 1732. William Blake was very successful self-publishing his work starting in 1783. Jane Austen was pretty successful – although, to be accurate, she went vanity press before there was a vanity press. Walt Whitman? Successful. Marcel Proust? Another success. Virginia Woolf? Success.
More successes include: Alexandre Dumas, Amanda Hocking, Anais Nin, Barbara Freethy, Beatrix Potter, Carl Sandburg, D.H. Lawrence, David Chilton, Dean Wesley Smith, Deepak Chopra, e.e. cummings, E.L James, Edgar Allen Poe, Edgar Rice Burroughs, Ezra Pound, George Bernard Shaw, Gertrude Stein, H.M Ward, Henry Thoreau, Hugh Howey, Irma Rombauer, J.A. Konrath, Jack Canfield, James Redfield, John Grisham, John Locke, K.A Tucker, L. Ron Hubbard, Lisa Genova, Margaret Atwood, Mark Twain, Michael J. Sullivan, Richard Evans, Rudyard Kipling, Stephen Crane, Stephen King, T.S. Elliot, Thomas Paine, Tom Clancy, Upton Sinclair, William E.B. DuBois, and Zane Grey.
Thomas Leo “Tom” Clancy, Jr. (April 12, 1947 – October 1, 2013) was an American novelist and historian best known for his technically detailed espionage and military science storylines set during and in the aftermath of the Cold War, and for video games that bear his name for licensing and promotional purposes. Seventeen of his novels were bestsellers, and more than 100 million copies of his books are in print. His name was also a brand for similar movie scripts written by ghost writers and non-fiction books on military subjects. He was a part-owner of the Baltimore Orioles and Vice Chairman of their Community Activities and Public Affairs committees.