As the saying goes, the plural of anecdote isn't data. I think the point here is that it's very much dependent on the niche and that your and other successful authors are atypical and doing better than most self published authors.
Whether or not that's true, I don't know. Maybe you are completely right. But we won't know from some anecdotes.
I didn't make the claim that every self published author makes a lot. I made the claim that you can make a lot by self publishing. The opportunity is there.
"You may have heard the phrase the plural of anecdote is not data. It turns out that this is a misquote. The original aphorism, by the political scientist Ray Wolfinger, was just the opposite: The plural of anecdote is data."
The problem with anecdotes is that we don't actually know what the cause of the results was. Maybe its the thing in question, but it could be something else either. That's the whole point of control groups (so you have a baseline to compare against and can filter out "contamination") and double blind tests (so you remove bias).
If you have suspect data, throwing more suspect data in the pile doesn't make it less suspect. Anecdotal evidence is just that: unproven possibly suspect data. Having more of these doesn't make it any more reliable.
So regardless of the original quote, I stand by the plural of anecdote not being data.
As the saying goes, the plural of anecdote isn't data. I think the point here is that it's very much dependent on the niche and that your and other successful authors are atypical and doing better than most self published authors.
Whether or not that's true, I don't know. Maybe you are completely right. But we won't know from some anecdotes.