For whatever reason, people in general prefer to pay for things, not knowledge. It's much easier to ask for $10K more of materials than it is for $8K more of consulting, even if the latter is actually 20% cheaper. Human nature.
The real problem is information asymmetry, it's more difficult to know that the consulting was good than to check that we have more materials.
It depends on how you spin it. People happily pay premium for smart offerings. They just have to see the reputation working.