I think the general feeling in the community is that the standard library is where packages go to die. Once something is in the standard library, it can't get meaningful features/updates outside of the yearly release cycle. pip and setuptools are already vendoring a TOML implementation, and once you have pip, you can pick from multiple great toml implementations that are all under active development. Maybe once the packages/standards for TOML are finalized and the only thing left to do is fix bugs, maybe then we'll see a TOML implementation in the standard library, but in the modern age where you can fetch dependencies at any time, there's honestly not that much incentive for CPython developers to take on more burden of maintenance and development for the already-massive standard library.