Let's be honest, the real 1999 design would have been a custom binary format that happens to use the endian of the system it was developed on, and leaks bits and pieces of unflushed memory buffers whenever it writes to disk.

Why XML bad?

What would you consider good modern design?

Welcome to 2026 unfounded hot takes.

Or less snarky: what's your gripe with zipped XML? It compresses reasonably well, has a useful structure, and has decades of mature tooling around it.