There are a lot of differences between storage formats. It would be incredibly difficult to create a universal query language. It would need to either a) change the storage formats so much that they're not really following their original standard, or b) create so many different versions of the query language that it's not really one standard.

Off the top of my head, SQL can't do lists as values, and doesn't have simple key-value storage. Json doesn't have tables, or primary keys / foreign keys, and can have nested data