They actually did a few years ago, but that's ancient history in AI terms.
The most recent thing they released was Whisper, which to be fair is the only model with absolutely no safety implications.
From what I remember reading, Open was never supposed to be like open source with the internals freely available, but Open as in available for the public to use, as opposed to a technology only for the company to wield and create content with.
They stopped releasing their stuff openly around the time GPT3 came to be.