so you can't name one brand. If so then advertising is working. when you went to go make a purchasing decision if that brand was even considered advertising did it's job.
My purchasing decisions are based mainly on whatever is the cheapest. I do find brands useful, to the extent that if a product is brand-name, it's likely to be more expensive than the no-name variety one shelf below. Saves some mental effort of comparing prices more closely.
The muesli I purchase is store-brand. I have made the decision by comparing nutritional content of a number of varieties.
I have been advertised to to get me to look at the nutrition labels, I suppose.