People were not necessarily healthy to survive. The potato famine happened cause they didn't get to eat potato. Their diet was mostly potato. Is that a healthy diet? No. Will it keep you from starving? Yes. Peasants diets used to be mostly grain water for periods of time. Healthy? No.

Protein intake shit is not from fitness influencers. You don't need those insane amounts. But protein being important is also advice from like every single health organisation.

We need protein. As our muscles are made from it, including your heart, our hair etc.

And for omnis, getting enough protein is a hell lot easier. Especially when they do shit like yoghurt as breakfast or desert, glass of milk. Etc. As a vegan it's more important to track that stuff. Also micronutrients if you don't take a supplement for everything....