It's right there in the article.

According to McDonald, "streaming music fraud is not, to be brutally honest, the most glamorous or profitable form of villainy" because "streaming rewards accumulate in tiny micro-transactions." The only way to get rich is to scale the shady streaming by becoming a business—it seems possible due to similarities in thousands of fake album designs that all the labels McDonald flagged could be under one licensor—but even then, "the larger the scale, the easier it is to detect," McDonald suggested.