Top Shelf is prime real estate in the book/publishing business. Eye level. Easily reached. No extra effort to find what you are looking for. The current hot sellers. New releases. Buzzworthy books. Retail chains like Barnes and Noble and Borders are incredibly picky and very intentional with who gets placed in a top shelf area. They not only choose wisely, but will charge publishers top dollar for the right for their authors to be placed "top shelf." Grocery stores and consumer goods focused retail stores are the same way. They put their best items on the eye level, top shelf area. Best-selling items deserve top shelf status.
Bottom shelf is for the laggards. Items on the bottom shelf are cumbersome to find, and you have to work to get to it. You can quickly go from a top shelf item to a bottom shelf item within one inventory cycle. Relax for a second, or one bad week of publicity, or a publicity nightmare like bad peanut butter or poisonous pills, and you are immediately but on the bottom shelf, or even worse, taken off the retail space all together.
Same goes with your company, brand or not for profit campaign. Staying "Top Shelf" requires constant innovation, improvement, quality control, and hard work. Bottom Shelf is easy, requires little effort, and becomes status quo. Second place vs. First place.
The question is, where is your company or church or brand currently? Top Shelf or bottom shelf?