Are those libraries actually not production ready as might be implied by the 0.x or are they just not willing to bump to 1.x for whatever reason? A lot of the projections mentioned in the submission seem to be production ready despite the version number.
They are widely used in production. Maybe some of them are de-facto production ready. But the developers don't want to make commitments to API stability.
And Python being Python it is very hard to statically enforce that you're upholding SemVer promises.
Only you can decide whether something is production-ready for you. The library author doesn't know what you're trying to do so they can't possibly know whether their library is ready to be used in your production. You could be making an experiment that's going to form part of a payload for a rocket, an embedded device that gets surgically-implanted into people, is life-critical and very hard to update or you could be making an online meme generator. Production-ready really does mean completely different things in these cases.
