> Dr. Hipp has said several times that nobody expected a weakly-typed database to achieve the pervasiveness that is observed with SQLite.

I don't remember ever saying that. Rather, see https://sqlite.org/flextypegood.html for detailed explanation of why I think flexible typing ("weak typing" is a purgative and inaccurate label) is a useful and innovative feature, not a limitation or a bug. I am surprised at how successful SQLite has become, but if anything, the flexible typing system is a partial explanation for that success, not a cause of puzzlement.