My guess is that Dr. Hipp’s (SQLite author) meticulous and prolific use of testing ferrets out so many bugs that the ones that are left wouldn’t be caught by static typing.

In contrast, folks who rely heavily on static type systems may not write so many tests. For example I put more energy into making sure that my Haskell types capture the problem I’m trying to solve, so that the compiler flags my mistakes and exposes poor assumptions.