I've commented on this before, but I'm Greek and our traditional cuisine has many dishes that are naturally vegan, in the sense that no meat or animal products are used in them, but nobody actually calls them, or thinks of them as vegan, only as "normal food". There's a list here, compiled by a vegan very happy to have visited Greece:

https://www.thenomadicvegan.com/the-nomadic-vegans-guide-to-...

I believe this is a common situation in many parts of the world. I thik most people eat meat only according to their needs. Especially earlier in human history, before industrial farming, meat would have been an expensive luxury for most people, who would have complemented their diet with fish, dairy and eggs, being naturally lacto- ovo- pescaterian rather than vegan, and would have eaten meat (especially beef) on special occasions like feasts and weddings and so on.

So maybe veganism is a reaction to the particular eating habbits of specific parts of the world, where meat is eaten too frequently?

In other places, like mountainous ranges, it would be pretty hard to get some sustenance directly from the ground, but again, goats are useful factories that turn otherwise unedible brush into food.

Most of the problem occurs because government subsidies make economical to raise cattle in places that should have no business doing so because there is plenty of better-suited environment in the third-world to free-range cattle.

Feeding grains to cattle in a high-wage first world country under confinement is way more expensive than buying meat for third-world countries in Africa or Latin American, and it only happens because of the lobbying power of farmers and agro-corporations.

I've read a serious attempt at finding out what it might be. All I can say is: Some people eat too damned much meat, but whether they eat 13× or 7× too much is a difficult question.

(EDIT: Sorry about the obscenity. I think the "bacon in milkshakes" got to me.)