IMHO, going production also requires scalability, high availability, and tooling ecosystem (backup/restore/replication), etc, besides functionalities and performance.
I would add SQLite is missing access control, it is a big all or nothing. Usually it doesn't matter as much since the scope is so much smaller, but if you really want to back a major website with it some defense in depth would be nice.
Good point! Security and regulation are other key requirements in real world for many industries.
Agreed. In the real world actually operating the database is just as important as its intrinsic query functionality.
Yes, that's also why certified Oracle DBAs can earn $$$ for their expertise on this.