That can’t be universally true - you can buy meat from independent farms. Maybe you’re correct about logistics at scale, but at the individual farm level, you can definitely purchase meat.

Random link from Google.

A friend of mine, her father was a bagging clerk at a grocery store for literally his entire life. He was able to support two kids and a spouse on that salary, and retired maybe ten years ago.

Broadly speaking, yes, having a mentor is a good idea. However, finding a mentor, a good one, is pretty challenging.

I feel like the pragmatic solution is just to try and find a good team. A good team will provide a learning environment for all of the best practices and technical skills.

There are a few mentor sites, but honestly, I’ve had pretty hit or miss results with them. You’d likely have to do some trial and error before finding the right fit.