It's human nature. OpenAI can continue without Sam, but not without Ilya for the moment. On the other hand, Sam could have been a little more "humble".
Sam is a VC guy who has been going on a world tour to not just get in the spotlight, but to actually accumulate power, influence, and more capital investment.
At some point, this means Ilya no longer trusts that Sam is actually devoted to the original mission to benefit all of humanity. So, I think it's a little more complicated than just being "jealous".