Instead of thinking of this as a benefit of wolves (specifically), you can view it as an advantage of having something in their ecological niche. In this case, the niche is 'apex predator.' It's a niche which is repeated across pretty much every ecosystem. They keep populations of their prey species down, preventing overpopulation and the many indirect problems that come with it.
Perhaps without an apex predator the prey species would evolve out of the overpopulation problem eventually. However, species that evolve with a predator tend to reproduce more quickly, which helps avoid being completely wiped out by the predator - when the population constraint impose by the predator is removed, the prey population explodes, leading to particularly pronounced problems.
(Perhaps if we had to contend with some homo-vampirus, we wouldn't have global climate change...)
Overall, humans already interfered in the shape of the ecosystem by removing wolves. You're correct that there's no objective 'correct' state for an ecosystem. But it is worthwhile to help balance ecosystems, especially when they have been unbalanced by our own interventions. Without restoration work, we're headed to a world with humans, livestock, and the few species that manage to live on our margins.
Perhaps without an apex predator the prey species would evolve out of the overpopulation problem eventually. However, species that evolve with a predator tend to reproduce more quickly, which helps avoid being completely wiped out by the predator - when the population constraint impose by the predator is removed, the prey population explodes, leading to particularly pronounced problems.
(Perhaps if we had to contend with some homo-vampirus, we wouldn't have global climate change...)
Overall, humans already interfered in the shape of the ecosystem by removing wolves. You're correct that there's no objective 'correct' state for an ecosystem. But it is worthwhile to help balance ecosystems, especially when they have been unbalanced by our own interventions. Without restoration work, we're headed to a world with humans, livestock, and the few species that manage to live on our margins.