I agree with you. But DBs are way more complex than most of the open source libraries. I know there are some pretty complex libraries but in most of the cases,

I agree with you. But DBs are way more complex than most of the open source libraries. I know there are some pretty complex libraries but in most of the cases, most of the libraries that the project depends upon can be easily replaced by some other alternative or organisation can dedicate some resources to fork and maintain it themselves. But migrating data from one DB to another DB can be a real pain.