I was wondering the same--I guess because it's fairly new (2018) and it came out of a database research group at a European university, rather than a SV tech firm. Therefore, limited marketing budget.

By the way, here's a YT video of a talk given by one of the DuckDB implementers about why they made it, what it's for, and how it works: https://www.youtube.com/watch?v=PFUZlNQIndo