If he's not, and literally all the other employees come back, its still a failure of the power structure that already happened. The threat of firing the CEO of the for-profit arm is supposed to be a unused threat, like a nuclear weapon.
He gets fired. Thats the enforcement mechanism.
Hence if he comes back, that indicates the board essentially "agrees" with Altman's positions now, however much Altman and the board's positions have shifted.