0.0001% = 1 in 1 million writers making a living from writing a novel. If only 100 novels made more than 6 figures in lifetime earnings, that means 100m writers didn't. Do you really believe there are 100m novelists out there?
Publishing, like music, sports and art, is a winners take most or all market. But I'm sceptical of the accuracy of the number you used. What's the source?
But mathematical literacy is as much of a dying art as the literary kind.