I can't even remember the last time I ate a MacDonalds
Anyway...
The referrals to large animals and grain are more to do with the amount of water & nutrients required to grow it. The theory is that in the future there will no be enough.
The vegans & vegatarians are incorrect in their belief that if everyone turns to a plant based diet, that it will make a difference. Wheat requires a lot of water & runoff to thrive. Also, you are still killing millions of small animals & insects everytime you toil a field.
Meat is nutritionally higher & you do not need to destroy large areas of space (as you do with grain & large livestock) to harvest it (as we all know). Wildlife can live alongside domestic animals as the garden blackbird & "quail" keep proving as they hang around together on the grass ("You'd better not catch anything!")
Technically you can get all of your nutrition from meat (if you eat the organs etc to). A plant based diet still requires vitimans B12 & additional calcium + iron to survive & thrive on.
Vitamin B12 is only found in meat foods from animals to bacteria. So, some meat is certainly healthy for us, but now it is not the way it has to be in this day & age (I think the vegans are right on that one.)
There is much more to it than simply the world governments, there is the land. Only so much % of it is suitable for agricultural purposes & we are currently using most of it. The rest is either protected wilderness or unsuitable due to soil drainage or other issues. So it's the environmental impact to consider to. Currently 60% of our world population of animals is going or has gone extinct since 1975 & most of them are because of agricultural practices & human housing developers. Our fences etc design a maze which our wildlife cannot navigate very well.
Building houses over current agricultural land is also happening faster than it is being replaced.
Also the agricultural practises are very damaging, but the governments & food agencies do not believe organic farming is sustainable in the long term on large farms.
They seem to think it is only sustainable on small farms or in backyard farming, but not suitable to feed the world. There are tests being carried out proving otherwise, but they are still sitting tight like ducks on this one.
They say they have no answers - I do. I say - lets all grow organic in our homes & gardens. Let vegans only grow vegatables & fruit & omnivores keep rabbits, chickens, quail & whatever other small suitable animals they can cook up (literally).
Now, explaining to the general public why there will have to be change 25 - 50 years down the line is another matter. I don't think anyone would listen

money is the priority until it becomes useless.
Scientists did do the lab grown steak, but personally I'm not keen on it
Anyway, come on people - would you live without big meat or not?

And to the people who replied yes & no already, thankyou for your answers.
Can you do votes on BYH....?