It's not bias, it's reality and the law of averages, not to mention murphy's law.
No one ever dreamed that the twin towers would be destroyed but it happened. Nobody thought we could beat the british in the revolutionary war but it happened. No one thought that alexander the great would be defeated in Afghanistan but it happened. No one believed at the time that the world was round but it was. Nobody ever dreamed that Toyotas were unsafe but they were. Nobody believed that there was ever going to be a black president but there is.