There are no absolutes. Things do get cheaper but you're ignoring several factors like scale, branding and just product awareness that make a difference for consumers.
Sometimes there are absolutes, as in this case. If ads benefit customers, they would seek them out. But obviously they don't value that "product awareness" and branding.
Branding helps in selection process. Product awareness helps in choosing a product to fit their needs. Coupons and other promotions are often sought after.
It seems you're unaware of what marketing actually is and are just personally against ads yourself. That's fine, but it doesn't mean there are any absolutes.