The go vegan and die meme strikes again, yet if I call you out on it, apparently I’m “snarky”. 沒辦法。
There are good reasons for people to want meat, yes, but it’s not a necessity for human life, so the oxygen analogy simply fails.
Getting back to the idea that brought this up (before I joined the discussion), for argument’s sake let’s say humans should eat meat, because evolution. But humans evolved as omnivores, not carnivores, so it logically follows then that there is such a thing as too much meat consumption (even JP doesn’t actually eat a pure meat diet despite the hype). So how much meat should humans eat?
Do humans (let’s say westerners) not already eat more, on average, than they did X centuries/millennia ago? Does that mean they have surpassed the ideal level? If they have, is it not desirable to bring the actual level of consumption back down to something closer to the ideal level? And would that not free up resources that are currently being used to sustain the excessive consumption?
(This is not to say humans don’t also consume excessive quantities of other things.)
As I said:
You can have cows. You can have whatever animals you want, if they support sustainability. The vegan challenge angle is that the animals can’t be eaten by humans, and – if we use the general flavor of veganism instead of a strict dietary definition – they can’t be treated cruelly. (Castration and euthanasia pass the test for many vegans. They have dogs and cats, after all.)
political ideology – the state controls everything (so every farm must follow the same model)
trade policy – if something can’t be produced on one farm, it effectively doesn’t exist for purposes of human survival (aka small scale self-sufficiency, aka hermitism)
If my reading between the lines of your nightmare is accurate, you’re running the experiment in a 1WG scenario. That kind of future is not within reach. You chose the UK (“Airstrip One”) and expected it to feed itself. It has a certain amount of land and a certain amount of humans, while other countries have other quantities and ratios. Think about it: if we’re talking about one farm, it can easily be predicted to fail the sustainability test if the challenge is simply to feed a certain number of humans that for historical reasons is arbitrarily high.
It’s the city-state problem on a larger scale: a megacity with a bit of farmland and forest attached can’t feed itself if it goes full hermit, so it imports food, and as long as it does enough stuff people in the outside world consider useful i.e. worth exchanging other stuff for, it will continue exporting and importing and… actually be sustainable.
If the farm in the experiment destroys itself by ruining its own soil or what have you, of course that doesn’t give it a high sustainability ranking and in the long run it could make the larger system fail. But if one individual farm produces an excess of foodstuff A and not enough of foodstuffs B and C to feed its fair portion of the population (wherever they happen to live), that doesn’t mean the model of that farm is unsustainable. It just means not all the farms of the world can be cookie cutter copies of one model. (Even soil depletion can be remedied through imports, if those imports are ultimately sustainable.)
(Also, if you insist on a 1WG scenario, then the state controls everything, so it can redistribute the population, and it can control population growth – not necessarily India-style or China-style, as it could be Singapore-style, or some other style.)
- agricultural policy – chickens aren’t allowed to eat certain forms of plant matter
Forget your tyrannical laws. Forget all the laws. Make your own laws. It’s a thought exercise, after all.
Eventually it needs some adaptation to reality if it’s going to work in reality, but if a law realistically can be changed, the first step is to make the case for changing it, e.g. “and the chickens on this farm will eat potato peels among other things, so the law banning that needs to change”.
- waste policy – green bins don’t exist because the state (which controls everything) doesn’t care
Do whatever you like with your human-produced waste. If the city produces an excess quantity that the farm can make use of, export it from the city accordingly. If you can’t fathom this working in real life, go check out the green bins that actually do exist in more and more cities. If the current green bin model is flawed, okay, let’s find a way to improve it.
(And again, if the state controls everything, it can mandate green binning. It can even mandate “night soil” collection and distribution, if that’s useful.) 
So if I understand your argument here, it’s that (1) the chicken-potato law and other laws like it can’t be fixed, so mass deregulation is the only solution. Yet how would you expect mass deregulation, in the era of factory farms, not to open the floodgates to bigger and worse things than we already have?
And that (2) deregulation won’t happen anyway, so… what, exactly?