Hugh Howey and Kris Rusch both have some good things to say about that fantasy that traditional publishing is gonna make you a star! 

Howey notes:

As for the 99.9% [of self-published authors] who won't see my level of success, I would point out that 99.9% of those who submit material to the traditional machine will never see a similar level of success. It isn't like our option is to self-publish OR see how well our novel does fronted out on an endcap in a bookstore. Our options are to self-publish OR spend a few years landing an agent, another year selling the book to a publisher, a year waiting for that book to come out, and then three months spine-out on dwindling bookshelves before you are out of print and nobody cares about you anymore. If you're lucky. Most likely, you'll never even get an agent. Because you aren't Snooki.

Could I agree more? No, I could not. I haven't had anywhere near the success of Howey, but I've come sooooo much further in two-and-a-half years of self-publishing than I did in the previous six years of trying to get published traditionally, it's comical. Hello--I HAVE TWO BOOKS OUT. That's two more books than I ever got out going the tradpub route. You can't sit around and say, "Your books would have sold more with a traditional publisher behind them!" because they never would have existed.

And Rusch points out that the headline earners will always be traditionally-published authors, not because they're necessarily earning the most, but because their information is being made available.

Every year, Forbes tallies up the “World’s Top-Earning Authors” and invariably, they’re all traditionally published. Why?  Well, Forbes explains it to you:

  FORBES bases its estimates on sales data, published figures and information from industry sources between June 2012 and June 2013.

In other words, the only place Forbes gets its data is through traditional media. If you earn a million dollars on your latest indie published title, well, that’s between you and your banker. Amazon doesn’t give out the sales figures, nor would Kobo or any other e-book publisher—because that’s your proprietary information. They don’t do it with traditionally published books either.

That information is released by the publisher. So if you’re an indie published writer, and you’re making tens of millions, the only way to get on the Forbes list is to broadcast your earnings to every damn media outlet you can find. (Which I would not recommend, by the way, since you’ll discover relatives that you never knew you had.)

I'll add that if we see the "world's top-earning authors" suddenly making less money, that won't actually mean that bestselling authors or authors in general are earning less. You can't get a good picture of the whole if you only survey one part.