This has been a common practice in physics, especially the more theoretical branches, since the inception of arXiv. Senior researchers write a paper draft, and then send copies to some of their peers, get and incorporate feedback, and just submit to arxiv.
It works for physics because physicists are very rigorous. So papers don't change very much. It also works for ML because everyone is moving very fast that it's closer to doing open research. Sloppier, but as long as the readers are other experts then it's generally fine.
I think research should really just be open. It helps everyone. The AI slop and mass publishing is exploiting our laziness; evaluating people on quantity rather than quality. I'm not sure why people are so resistant to making this change. Yes, it's harder, but it has a lot of benefits. And at the end of the day it doesn't matter if a paper is generated if it's actually a quality paper (not in just how it reads, but the actual research). Slop is slop and we shouldn't want slop regardless. But if we evaluate on quality and everything is open it becomes much easier to figure out who is producing slop, collision rings, plagiarist rings, and all that. A little extra work for a lot of benefits. But we seem to be willing to put in a lot of work to avoid doing more work