Technological advancements and the birth of hardcore customer service subsequently forced most businesses to specialize, leading to plumbing wholesalers, for example. So, that was the next movement in the cycle and it was successful for a number of years.
The age of communication and globalization has more recently driven the next cyclical movement, back to more of an integrated supplier environment. But, this time there's an interesting little twist. Instant communication has shrunken the world and given buyers access to a vast community of sellers. This has led to a buy-direct mentality, making most products commodities. Hence, the integrated (large-scale, wide offering) distributor. However, this time around, customers are still seeking specialized assistance. And, while they may not necessarily be willing to pay more for it, they will sway their buying decisions toward suppliers that offer it. Success today often means an integrated offering, with access to all of the conveniences and assistance of a specialist.