Why would anyone share their moneymaking method?

What is the reason for money making methods being leaked?

There is a number of reasons whereas some are more intriguing to look at. First and foremost, most people who leak a money making method or rather an e-book is not the original content writer. In other words, without correct statistic and based on my own assumptions, most if not more than 80-90% of the cases where a method or e-book is leaked, the owner and/or the writer is not the one(s) leaking the method. 

Now the reason could be someone who bought, paid, got a vouch copy or were tasked with something like proofreading, had a fall out with the owner of some sort, or simply just being a dick as @Suave said above, which leads to the method being leaked on multiple platforms. Sometimes this also leads to the owner having to stop sales of the e-book or innovate the method to keep selling.

For any other reason as to why they are being leaked, I think those don't really have to be commented more on.