> I never took SQLite seriously for the very reason that field types were not enforced by default.

I can understand not taking it seriously if it was completely unsupported but I'm pretty sure most databases don't have perfect default configs. Even PostgreSQL needs configuration for optimal performance because the defaults are for low (minimum) spec systems.

> then eventually adding nearly all the reliability facilities of TCP to the app (automatic retry, etc) by hand.

Depending on what you're doing you're still probably doing better than TCP after all that work. TCP is a stream based protocol which is not ideal for many applications due to head of line blocking. If you built your own reliability layer over UDP you likely avoid that issue entirely.