In a multidisciplinary and global domain, it is unrealistic to expect that all software components use the same specification to interoperate. Brokers provide the bridge between communities using different specifications -or different (valid) implementations of the same specifications.
Having diverse communities is a strength, each with their own standard. So while there is a drive to adopt common specifications, e.g., standards, this singularly will unlikely be achieved for complex and global domain -like the multidisciplinary Earth Sciences domain. Brokers and standards are complementary.