I think there's a lot of misunderstanding about what makes a brand. It's very often talked about entirely in terms of image, marketing, and target audience, and the actual product and customer experience gets left out of the picture. That this isn't a sustainable position is neither new, nor a product of the rise of the Internet.
For established brands, this is a nightmare. You can never coast on past performance—the percentage of brand-loyal car buyers has plummeted in the past twenty years—and the price premium that a recognized brand can charge has shrunk. If you’re making a better product, you can still charge more, but, if your product is much like that of your competitors, your price needs to be similar, too. That’s the clearest indication that the economic value of brands—traditionally assessed by the premium a company could charge—is waning. This isn’t true across the board: brands retain value where the brand association is integral to the experience of a product (Coca-Cola, say), or where they confer status, as with luxury goods. But even here the information deluge is transformative; luxury travel, for instance, has been profoundly affected by sites like TripAdvisor.