There's a lot of space to go around though, most of it undeveloped for e.g. agriculture, and a lot of developed space is under-utilized due to focusing on livestock.
Not really. There is a finite amount of arable rich land which can support life. A lot of "space" is frozen or desertified wasteland.
> most of it undeveloped for e.g. agriculture
Agriculture is the most destructive human enterprise. Most of the animals ( insects and rodents ) that are killed are due to agriculture. You have to kill all the animals in the land to create a farm. Then you have to constantly spray insecticide and herbicides to keep animals and weeds off the farm.
> and a lot of developed space is under-utilized due to focusing on livestock.
Raising livestock is far less destructive than agriculture. Primarily predators like coyotes, wolves and bears are victims of raising livestock.
