Do those figures include the fact that agricultural land can't be used every year for growing fruit and veg? Or areas of the world that struggle immensely to grow fruit and veg?
Deforestation also happens for produce that takes a higher profit anyway, so if that's not a cow, it'd be something else... a yam, say.
I appreciate this reads slightly confrontationally, and I don't necessarily mean it to (give me the answers to the questions, and I'll look into it / test it out as a hypothesis), but I am struggling to get my head around how scaling things up works. Hunter / gatherers augment what they farm (limited) with meat, after all, with no real detrimental effect, but they're not doing it as a mass-market industry.