When it comes to products, marketing is also one of those dimensions, and can easily swamp the others. It's a good assumption that if you hold price steady, the more marketing, the worse the product. We don't see this because it is often canceled out by economies of scale, which of course are a result of size, and the larger the relative size, the higher amount of marketing as compared to other brands.
At the same production scale, you should expect the most marketed product to be the worst.
There's a school of thought that expensive advertising is actually "signalling" higher quality to consumers. Why spend so much on something substantially less appealing than available substitutes?
It doesn't help that size is partially a result of marketing. At the same production scale, the most marketed product may not be staying at that scale as long (assuming the marketing is being done somewhat efficiently, which perhaps isn't necessarily a good assumption).
At the same production scale, you should expect the most marketed product to be the worst.