My understanding is that land used for livestock is often not suitable for crops, water is mostly rainwater, and animals are fed the grain deemed not suitable for human consumption?
I think things like nut processing use much more resources overall than milk from a cow
Not at all. While animals can be pastured, most of the livestock in developed countries is reared in grain-fed CAFOs. These are, in most cases, grain that is suitable for human consumption or could be made so. Moreover, almond milk is still ecologically preferable to cows milk.
Life is already hard enough for people with nut allergies (which is apparently more common than I thought), so let's just make that oat milk and call it a day. A lot better for the environment too :)
"most of the livestock in developed countries is reared in grain-fed CAFOs"
That simply isn't true. It is very, very common in the US. I've not seen a trace of it in Norway: Farmers here seem a bit appalled. From what I understand, at least some aspects of this sort of farming have been outlawed in much of Europe, and Europe is full of so-called "developed countries".
I think things like nut processing use much more resources overall than milk from a cow