We're not talking about a extra week of hard work here and there, it's months of sustained 80-100hr work weeks. You're so exhausted after just a few weeks that you make a ton of stupid fucking mistakes, which compounds the whole situation.
If crunch worked you'd see it more widely across our industry, however it has the benefit of both burning out people and putting them in a state where their output is lower than it could be at sustained reasonable hours.
Any asshole who thinks otherwise needs to be called out on it.
Source: Ex-gamedev, where I watched crunch crater two different studios.