If you're selling a business to business service and you can prove that it's better, that it delivers more value, that it's cheaper or more durable or more efficient, shouldn't that mean you will close every sale?
Even hard-headed business people end up buying the thing they want, not the thing they necessarily need.
The real danger of relying on facts to make your sale, though, is that when the facts are no longer on your side, you're toast. The low-cost supplier gets hooked on the easy sales that come from acting like a commodity, and if that changes, you've got little room to maneuver.
Great brands and projects are built on real value and a real advantage, but great marketers use this as a supporting column, not the entire foundation. Instead, they build a story on top of their head start. They focus on relationships and worldviews and interactions, and use the boost from their initial head start to build competitive insulation.