It seems like the board wasn't comfortable with the direction of profit-OAI. They wanted a more safety focused R&D group. Unfortunately (?) that organization will likely be irrelevant going forward. All of the other stuff comes from speculation. It really could be that simple.
It's not clear if they thought they could have their cake--all the commercial investment, compute and money--while not pushing forward with commercial innovations. In any case, the previous narrative of "Ilya saw something and pulled the plug" seems to be completely wrong.