The grass hills are beautiful, it would be a great shame to see them converted to crops. I would argue they won’t be, and therefore the cattle raised on them is effecient.
In 2010, the British livestock industry needed an area the size of Yorkshire just to produce the soy used in feed. But if global demand for meat grows as expected, the report says, soy production would need to increase by nearly 80% by 2050. [2]
From a completely theoretical standpoint, if humans were to stop consuming meat we would actually need to close 1000's of crop farms, not open them on rolling hills, even when accounting for our dietary increase in plants. I'd therefore argue that it's a shame the land has to be used for agriculture at all. Better would be to maintain them as national parks and the like.
[1]http://www.sciencedirect.com/science/article/pii/S0959378017...
[2] (PDF WARNING) https://www.wwf.org.uk/sites/default/files/2017-10/WWF_Appet...
So in our current system it does appear that cattle, even if they occupy some grassland space which could not be more efficiently used, do inevitably use resources which could be more efficiently used to feed humans directly.
(I have no idea if there's an efficient way to scale beef).
If you're interested, https://twitter.com/drsplace is a good follow. She writes and cites a lot on this topic (because she is employed by the beef industry).
From another article ( https://www.cnet.com/news/impossible-burger-2-0-tastes-like-... ):
> But Impossible Foods can produce a burger using a fourth of the water and less than 4 percent of the land -- and emit one-tenth of the greenhouse gases -- than a conventional burger, Brown said.
So yeah, we might still destroy forests to make veggie burgers, but it'll be 1/25th of the forest destruction (if you believe the numbers).