Not sure how that is related to your statement about markets, but your other point is easy to answer: we have to think about the conditions humans existed in. We lacked science, all the innovations we have in the farming industry, the ability to specifically analyze what nutrients we could be lacking. Without these, our ability to dial in a diet was lacking, famines were unpredictable, and in general we could only deduce what was needed to a certain degree. Meat helped shore up those short comings. Today, we know why people crave meat: their microbiome is accustomed to it, there is a societial pressure to eat it, it's affordable and overall accessible. Those previously listed limitations are no longer: we can plan a 100% healthy meal that covers everyones needs and with a centralized plan we can appropriately farm what is need for everyone. However the current systems are not designed to accommodate everyones needs, it is focused on generating commodities, so until we can stop the system that forces people to be dependent on meat, we cannot stop the meat industry from existing.

I hope that made sense!