When I look at comparisons like this, one of the first red flags I check for is binary size. First SQLite:

https://sqlite.org/2022/sqlite-tools-win32-x86-3390200.zip

Result: "1,108,480 sqlite3.exe". Then DuckDB:

https://github.com/duckdb/duckdb/releases/download/v0.4.0/du...

Result: "32,052,736 duckdb.exe" (already stripped)

To me, this says that SQLite is a carefully considered codebase, with great care put into making a lean and high quality piece of software. While DuckDB seems to have the hallmark of bloated C++ code, with plenty of waste, and little care to these details.