In some ways, writing a novel (or producing certain types of works) is like buying a lottery ticket. Most of the time it will be worth nothing. But if it is a winner, then the buyer would like to be able to cash it in. If, on the other hand, you couldn't win the jackpot even if you hit all the numbers, then people would stop buying lottery tickets.

The purpose of copyright is to encourage people to write or produce creative works, even when the reality is that most works will not be successful in any way. If you take away the possibility of reward for the few works that are successful, then that will result in fewer works being produced.