I haven't used duckDB but the real comparison is presumably postgis? Which is also absent from the discussion, but I think what the author alludes to.
I have no major qualm with pandas and geopandas. However I use it when it's the only practical solution, not because I enjoy using it as a library. It sounds like pandas (or similar) vs a database?
Yeah, PostGIS is readily available, and postgres is much more widely used than DuckDB. Either I don't understand OP's argument for why this is so important or I just don't buy it.
If you're using JavaScript you install Turf. The concept that you can readily install spatial libraries is hardly earth shattering.