You are right.
AWS did not acquire the DuckDB technology itself, which is MIT-licensed open source and governed by the DuckDB Foundation which holds most of the related IP [1].
What they did acquire is DuckLabs, the Amsterdam-based services and development company behind the technology which is owned by and employs the creators and major contributors.
And MotherDuck is a US-based venture-funded commercial company, whose cloud-based data platform is centered around DuckDB but has been significantly expanded recently, including Python pipelines, an agentic context layer, and a visualisation layer.
smells like redhat
Interesting to see how they will update their About page.
Currently it says “Today, DuckLabs remains independent and fully owned by the original creators. We've deliberately chosen not to take venture capital, so we can focus on sustainable engineering, correctness, and keeping DuckDB open and MIT-licensed for everyone. “
Future will tell if that ends up being true.