If you have an underproductive department with overprotective management, layoffs (and negative performance reviews) won't happen as frequently as they should.
Maybe members of management just want to protect their respective fiefdoms. Maybe they have their empathy makes it difficult to lay people off. Maybe they genuinely believe their teams are doing well. Maybe their teams actually are doing well, and exceptionally few layoffs (if any) need to happen.
Regardless, "because Marissa said so" is a perfectly valid answer. There will be collateral damage, but it's likely that she's dealing with some extremely protective, entrenched management who won't negatively review anyone on their teams unless they're forced to.