Earlier quoted context omitted.
Of course all companies use ads, including unscrupulous ones. But ads work better for companies with a real product, and therefore you expect the % of good products among advertised products to be higher than among non-advertised ones.
> But ads work better for companies with a real product, and therefore you expect the % of good products among advertised products to be higher than among non-advertised ones. [citation needed]
The mechanism for the first is quite intuitive. An add can make someone buy something once. If that thing is good, there is a chance they will buy again, and so give you more money. If it is not good, they will at most buy it once.
So the EV of an add on a good product is by definition higher than one on a bad product; and so a company with a good product should be willing to spend more on an ad.