Just my 2cents:
Digestability changes (things akin to Rot/Spoilage) occurs in things like bananas, yams, milk, coconuts. If you have a bowl of fresh fruit, thats pretty good. But if you juiced that same bowl of fruit, threw it in the fridge, returned to it nextday and drank it. Its entirely different drink thatll only process as sugar.
Same as above applies to meats and there is a huge difference in taste and how body processes it based on similar factors above. Lots of "meats" consumed in usa tend to be processed, and pretty stale and reflects poorly on health.
However, a pathway many have found for their optimum health includes consuming lots of fresh redmeat, fish.
The societal, biological, and psychological ramifications are important to consider. An inconvenient setup and task for each family to locate, connect with, raise, and locate and butcher their own animals for meat, I'd agree would be an imrovement but unlikely in modern, "civilized" global cities.