It would be awesome to have actual open source (and open weights) models! I hope someone will make a real go of this at some point.
https://allenai.org/ is what you're looking for
Yes, I've seen it! It's exciting, but I don't have enough information to say whether they are making "a real go of it". That is, it's unclear to me whether they have the tens to hundreds of billions of dollars necessary to create a frontier model.