The buyers power is unquestioned, but the sellers opportunity is merely possibility and not a guarantee. Only in some models. Few companies build, sell, and ship their product themselves. Often 3 or more companies are involved. That's why Fedex and UPS market themselves as ecommerce companies for their role.
Every product is available everywhere.
The gap between desire and purchase has closed. The problem here, and what they fail to mention, is that the impulse has changed. If your price seems too high, they'll go elsewhere. People are self interested, so are companies. People need a powerful incentive to change their behavior Sex sells.