Seems like a good plan, but the problem is that the available land is scarce and we only have one planet.
So we'll have to choice either to undig (and uncontaminate) the fertile lands under the roads and streets in the urban areas, that is a way;
or instead burn the last forests and give our precious natural areas to the pigs, literally. The pressure to ocuppy still relatively intact areas and the last protected sanctuaries for biodiversity would be irresistible and inescapable.
And is a wrong (but much repeated) idea than we'll stop the suffering. Is just that they are conveniently dismissing the suffering caused to the ecosystems. "Gazillions" of savage animals, plants, trees and fungi will suffer inmensely if we scalate the solution to all our cattle.