The truth about most indie comics is that indie comics sales figures aren't real sales figures at all. In truth, most black-and-white indie comics in the 90s, if they were lesser known, sold, on a good sales run, 2,000 to 4,000 copies in comics shops. And that was when indie comics were most popular, the 90s. The only comic book series that sold more than that low market figure were the ones everyone's heard of.
So in indie comics it's not really about getting rich. Sales are pretty much irrelevent. No one's getting rich off of sales figures that low, and yet it's still considered the norm to publishers of black and white indie comics.