tomlkit is not abandonned in any way but between Poetry, Pendulum (which is being reworked) and other projects I am spread pretty thin. Tomlkit was born from a need for Poetry to have a style-preserving parser/formatter and I updated it for each TOML spec bumping. So it’s currently compliant with the latest version of the spec.
And, honestly, saying it sucks while pipenv jumped on it when it was released is ironic at best, cynical at worst.
As far as I know there are no other style-preserving parser out there, in any language, so I had to take it upon myself to build my own from the ground up. And apart from @frostming – Sorry for not getting back to you about the proposition to co-maintain tomlkit, hit me up if you still want to talk about it – no one here that complained about it has stepped up to help with its development.
Is tomlkit perfect? No. Does it have bugs? Yes. Does it fit in the standard library? No and a full-featured library does not make sense to be integrated in the stdlib in my opinion.