This quote is broadly recognized in economic settings as true, but few in the knowledge management space place emphasis or focus on designing both simple systems which are easy to master and use on a regular, ongoing basis. This allows the knowledge worker the ability to more quickly (almost blindly) handle their indexing and filing operations so that things are precisely where they need them when required for use.

Poor design will not only decrease the ease of use, but also discourage the user from both efficiently using and benefiting from their systems.

Even simple and efficient filing systems require familiarity and expertise for them to effect useful gains to their users, and prove their effectiveness over time. If a user can't get to a basic level of functionality in short time, they're likely to give up on it and never see the ultimate benefits.