A proportion of the world is also malnourished because they cannot afford the foods they need (which contain animal product) to thrive and cannot pop to the shops for supplements or vegan food which are fortified with the correct nutrients.
In some parts of the world, people's diet is dominated by meat because that's what's largely available.
In the parts of the world where people live the longest, diets largely consist of lots of unprocessed plant based food, but pretty much all of them are supplemented with various amounts of animal products, particularly fish.
As I said, I totally agree that we eat waaaaaay too much animal product in the West, health wise, for the planet and because such intensive farming means the animals are not treated well. This will absolutely have to change. I have certainly cut down massively on how much meat I consume, I probably still eat too much, but I would never cut out animal products completely.
I'm just saying it's pretty ignorant to think that 'the world will become plant based' or that that would ever be possible.
I am trying to live by the rule of 'Eat real food, not too much, mostly plants' now. I don't think most Western diets, both meat eating and vegan (plant 'milks' with loads of stuff added in probably don't count as 'real food', unless you make your own, and certainly not all these fake meats that are on the market now) come under this.