If I am archiving PBs of data for 10+ years, I don't want to rely on a WASM interpreter being available and performant in the future just to read a file. I want a dead-simple, heavily documented byte specification like Parquet.

Additionally, putting the decoding logic inside an WASM binary introduces an active execution layer into what should be a cold storage.

WinRAR format does include RAR VM bytecode as part of the archive to achieve state of the art compression in media files. it was sandboxed and well accepted by everyone.

the same sandboxing capability exists for WASM as well.

it is actually better for long-term archival: you dont need to carry decompression program, since it will be a part of the archive file itself

You don't want to run a custom 10-year-old data parsing function every time you read a single data record?