This is a very real problem being addressed here and I am intrigued by all the great comments in this thread.

In the Zed project, we've been thinking about and iterating on a better data model for serialization for a few years, and have concluded that schemas kind of get in the way (e.g., the way Parquet, Avro, and JSON Schema define a schema then have a set of values that adhere to the schema). In Zed, a modern and fine-grained type system allows for a structure that is a superset of both the JSON and the relational models, where a schema is simply a special case of the type system (i.e., a named record type).

If you're interested, you can check out the Zed formats here... https://github.com/brimdata/zed/tree/main/docs/formats