Kris Rusch has a thought-provoking blog post in which she looks at Joe Konrath's sales numbers. What's interesting is that she makes the case that he is still, even today, basically a mid-lister--his sales are good, not great.
And yet, he's making buckets of money.
I know I've brought this up before, but I just feel like doing the happy dance whenever I see something like that--writers making a living (or waaay more than a living) off of sales that would be of zero interest to large publishing houses. There's a big difference between 70% of the pie and 10%.