1. They are not going to include everything. This includes things like new file formats.

2. They are going to be out of date whenever a standard changes (HTML, etc.), application changes (e.g. SQLite/PostgreSQL/etc. for SQL/ORM bindings), or API changes (DirectX, Vulcan, etc.).

3. Things like data structures, graphics APIs, etc. will have performance characteristics that may be different to your use case.

4. They can't cover all nice use cases such as the different libraries and frameworks for creating games of different genres.

For example, Python's XML DOM implementation only implements a subset of XPath and doesn't support parsing HTML.

The fact that Python, Java, and .NET have large library ecosystems proves that even if you have a "Batteries Included" approach there will always be other things to add.