Meat isn’t something we started eating when we became humans. I am pretty sure chimpanzees eat animals, though I think it’s mainly insects. Our specific strategy for hunting might have something to do with us developing intelligence but that isn’t certain by any means.

Anyway lots of countries are not this meat centric as meat is more rare and expensive.

It is somewhat more difficult to have a perfect diet without meat. Then again having a healthy balanced diet is general is difficult no matter how many animal products you use.

I also think you missed the point of being vegan entirely. It’s to stop suffering, not because of nature or being healthy.