That's not really random access, though. You're effectively just searching through the entire dataset for every targeted read you're after.

What might be interesting is to have a tool that processes full JSON data and creates a b-tree index on specified keys. Then you could run searches against the index that return byte offsets you can use for actual random access on the original JSON.

OTOH, this is basically just recreating a database, just using raw JSON as its storage format.