Donovan Murphy did not want his dead relatives to be reanimated or customized. He only wanted two things in life: to die quickly and to give his family financial independence. He got what he wanted, but... You know what, I'll get right to the point.
The zombie apocalypse finally happened, but it didn't cause as many problems as we imagined it would. Why? Implantable brain-machine interfaces.
It's funny to think that the undead eventually became the not-so-expensive alternative to robots. And then we customized them and made them work for us, and finally, we put them to fight for our own amusement.