Why would anyone in their right mind invite such a man to lead a commercial research team, when he's demonstrated quite clearly that he'd spend all his time trying to sabotage it?
This idea that he's one of the world's best researchers is also somewhat questionable. Nobody cared much about OpenAI's work up until they did some excellent scaling engineering, partnered with Microsoft to get GPUs and then commercialized Google's transformer research papers. OpenAI's success is still largely built on the back of excellent execution of other people's ideas more than any unique breakthroughs. The main advance they made beyond Google's work was InstructGPT which let you talk to LLMs naturally for the first time, but Sutskever's name doesn't appear on that paper.
https://scholar.google.com/citations?hl=en&user=x04W_mMAAAAJ...
Does OpenAI still need Sutskever? A guy with his track record could have coasted for many, many years without producing much if he'd stayed friends with those around him, but he hasn't. Now they have to weigh the costs vs benefits. The costs are well known, he's become a doomer who wants to stop AI research - the exact opposite of the sort of person you want around in a fast moving startup. The benefits? Well.... unless he's doing a ton of mentoring or other behind the scenes soft work, it's hard to see what they'd lose.