I think your view is too simplistic. You are wholly correct that it's good for scientists to publish data, and often progress is made when scientists see each other's data. However, often it's not practical to publish all data or knowledge about an experimental set up. Many of my experiments run on custom-built machines with years of maintenance and history. Detailing every step in a machine's history is far too onerous a requirement, even if it does occasionally contain a nugget of value. As rprospero says above, what counts as data? An important part of scientific publishing is having the judgment to know what to include and what not to include.