I’m with you. 80/20 is the lowest I have seen in real in-store ground beef. There may be tubes of higher fat meat in Walmart, but really, who buys meat in a tube?
The real conundrum is that with beef you pay more for less fat; whereas with milk you pay more for more fat.
Avoid the cost-push fallacy!
The price is determined by what the customer will pay, not the cost of production!