Outright confirmed for the worst at the end of Act II that the machines are practically obliterating all of Hell, having successfully destroyed all of the Limbo and Lust layers in their entirety and making fast progress through Gluttony by the time of the rematch with Gabriel.
The fact that said unstoppable blood-fueled robots now have their eyes set on the Afterlife isn't making things better and at the rate they're going, any kind of life will probably be non-existent once they are done. Killer Robots are literally fueled by blood, and they wiped out all life on Earth, leaving the planet a desolate husk of itself. The game's premise is terrifying on its own.
