It's easy to understand why -- pre-XML, data exchange formats were generally binary or otherwise non-readable. But once storage got generous enough that each byte stopped mattering, people looked for a textual data format that was easy to debug, and XML was available.
Still, it does make we wish a happy middle ground could have been found. An open standard something essentially like a compact binary format (similar to protobufs) but with a schema with field names and defined structure required at the top of every file. Which would require a dedicated app to view it, essentially similar to JSON once parsed. (While not transmitting the schema during communications but hard-coding it into the sender and receiver could serve as a poor man's obfuscation.)