I am the author of the original post and I also wrote a followup blog post on it yesterday: https://szarnyasg.org/posts/duckdb-vs-coreutils/

Yes, if you break the file into parts with GNU Parallel, you can easily beat DuckDB as I show in the blog post.

That said, I maintain that it's surprising that DuckDB outperforms wc (and grep) on many common setups, e.g., on a MacBook. This is not something many databases can do, and the ones which can usually don't run on a laptop.