That doesn't sound like a solution, and it is not attainable at all unless we are talking about thousands upon thousands of years. Meat is culturally important, and only a small percentage of the global population is willing to give up on it.
PS: When you talk about mammals only, are you still pro-consumption of fish and avians?
No, I think fish and avians should be avoided for consumption as well but the article is about beef and we need to start somewhere. Cows are sentient emotional social animals as we are.
You could use Quorn instead and just eat more of it. It has less protein by weight, but more for the same number of calories. Also beans are very good.
I believe you are misinformed. Brazil is the top exporter in the world of several agricultural products and metals. Beef is not even in the top 10 exports from Brazil to the US.