In addition to Postgres FDWs, Steampipe plugins are also available as a SQLite extension [1] or a CLI export tool [2] for lighter weight use cases. (Although a local Postgres has a surprisingly small footprint!) Building plugins as DuckDB extensions would be cool too, but we haven't done that yet.
I last played with it over a year ago and I see that blog post is from Dec 2023. Looking forward to trying out the sqlite extension.