Are media organizations like 9to5mac (mentioned in Apple's memo) paying Apple insiders for the information they provide?
Personally, I wouldn't think that the leakers were getting paid. Even if they were, I imagine the amount that these particular online web sites are able to pay is very much -- especially when compared to the average Apple employee's salary.
This makes me think that money isn't the primary motivating factor, if it is a factor at all.