Harm is done to the ecosystem when we concentrate cows in one place and feed them chemically fortified slurry. When cows are allowed to graze pastures, they instead have a positive effect on the local ecosystem.
As such, I am extremely skeptical that the right way forward is to reduce and concentrate the essence of a cow into bioreactors and feed them chemically fortified slurry.
I'm interested in those answers, too. I imagine it's much less waste because you can feed the cells just what they need to grow, instead of feeding the bacteria in the guts of an animal.
You ignored the part of the GP comment where they agreed with you. The point is that properly managed pasture increases fertility naturally. We need animals to fertilize, or every plant must be grown with synthetic products.
As such, I am extremely skeptical that the right way forward is to reduce and concentrate the essence of a cow into bioreactors and feed them chemically fortified slurry.