There are a variety of channels available and customers will use different channels for different purposes. Carting home a bag of potatoes is just not a happy thing to do. However, if it is a luxury item, the experience of shopping for it and physically going somewhere is actually quite pleasant. Going and buying a BMW on occasion or a Mercedes Benz or a Ferrari is actually an experience. The smell of the leather, the scent of the petrol, the cappuccino coming out of the antique machine in the dealer's showroom is all an experience.
Luxury items are an experience.
The basics are about convenience. If you can substitute it at a relatively low cost, then you will. Alternative channels depend on the customers. Alternative channels will also be driven by manufacturers who want to get direct access to their customers instead of going through intermediaries. Automotive manufacturers make very small margin on the actual manufacture of motor vehicles.