For every A+ list actor making millions per film there's tens of thousands of starving wannabes trying to get a break working for half nothing.

For every footballer making 100K per game there's tens of thousands of teens trying to break in making nothing.

For every A list author there's a hundred thousand people pouring their heart and soul into a book that few will ever read.

Pratchett was an exceptional human being.

He was 1 in a million.

But there's 7000 people who are one in a million and only 10 of them get to be in the top 10 best selling authors of the decade.

Making your choices based on the expected return of an investment isn't proven to be a bad idea by pointing to people who've made tens of millions from the lottery.

Pratchett was exceptional but there's a good chance that if at the start a few reviewers had been more negative, if he'd been feeling a bit off while writing some pieces that the discworld may never have become what it did.