[throwaway5752]

There are actually 8.1 billion humans. Say that everyone wants beef for dinner, .5 lb / person, rounding down to 3 lbs weekly, rounding down to 150 lbs per year. That is 1.2 trillion pounds of beef per year. The real number is much lower due to age demographics, dietary choices, and poverty (about 60 lbs per person, per year in just the US) but let's keep it simple;, "If everyone in the world wanted 3 lbs of grass fed beef a week, how would that work out?"

400 lbs of meat per head of cattle is 3,000,000,000 cows. 5 acres per head of pure grass fed, double number of animals because of average slaugher at 2 years, and that is 30 billion acres devoted to grazing. For context 125 million acres are utilized for cattle (feed and grazing) in the US. Globally that is 3 times more than is used for all agriculture, globally. This is ignoring dairy.

So this is not very tricky. It is wildly unrealistic for grass fed beef to be anything but an extreme luxury food without large numbers of people starving.