It's amazing the lengths people go to reduce things into two dimensions.
popular and quality product vs cheap junk and snake oil (and presumable unpopular)
An honest person would note all possible combinations in their simplified model of businesses seeking advertising
1. popular products with bad quality
2. popular products with good quality
3. unpopular (or unknown) products with good quality
4. unpopular products with bad quality
And of course the real world is more complex than this.
your analysis is bad and wrong.