I can't believe all those hundreds of thousands of listings would continue to exist if there weren't some kind of pay off. Somebody's got to be making money somehow, as it's been happening for ages.
Also, it makes searching difficult. Can't really sort by price anymore, because the lowest prices are almost entirely scams.
It's just a much less pleasant platform when half the listing are fake. This is most extreme on GPUs and RAM, of course, since that's where the feeding frenzy is happening, but it's true of many categories with expensive goods.