> So on a plant-based diet you can't save yourself?

I'd generally go for keto since that is more studied compared to strict carnivore.

> Plant-based meals require far fewer resources and is cheaper, which means maintaining societal stability when resources are becoming low - as there is more to go around.

But your health will (probably/maybe) be worse. There are ways to make cheap keto (ex: eating 10 eggs/day in my local area).

> A lot of farm land is being used to grow foods for livestock. We could use that land to grow food for ourselves.

Then eat grass-fed meat. I do so myself.