Recently I visited a plumbing wholesaler that operates a number of high-end showrooms. Like almost every merchandising wholesaler, this company has procedures to include plumbing contractors in the sale. All a contractor has to do is escort or at least refer a customer to the showroom and be able to document the contribution. The wholesaler has a registration program set up to reward contractors who do this.
This wholesaler, like most in our industry, prefers to sell through contractors. Otherwise, the wholesaler has to take charge of scheduling, delivery, changes, returns, troubleshooting, etc. For the contractor to handle these details is worth the margin the wholesaler gives up. That's why this wholesaler does little consumer advertising but a bunch of trade promotion.