Livestock can subsist on plants, like wild grasses, that are unpalatable or even inedible to humans. These plants often grow on "unarable" land that won't support human crops. For millennia, humans raised livestock on pasturing lands, seemingly without harming the environment too badly. What stops us from doing that now?

I suspect the real problem is closer to wasting arable land, water, shipping (with all of those environmental externalities), etc. on growing crops that aren't used to directly feed humans, and government subsidies that hide the true cost of corn-fed livestock from consumers.

We don't need to use that land though. If we're not feeding livestock then we don't need near as many crops to support ourselves so let the unusable land return to the wild.

Also if you want to use scrub land to feed your livestock you're going to need a lot of it like in Australia.

>For millennia, humans raised livestock on pasturing lands, seemingly without harming the environment too badly.

For millennia most people wouldn't be getting access to 200lbs of meat a year. There was also a lot fewer of us to feed that much meat to.

Yes, and the high demand for animal based proteins has been a large cause of deforestation. Also, beef and other livestock produce a large portion of green house gas emissions.

Problem is getting plants to taste as good as meat.

People who don't have meat based diets tend to not agree that meats taste good(after some time if they were heavy meat eaters before). So the solution is to start kids on meat free diets and keep them on them then within a generation most people won't think meat tastes as good as plants. Problem solved.

I'd love to see studies on that. My personal anecdotal experience has not been that nor has it been that for friends and family who have tried vegetarianism/veganism, but it'd be heartening to see that there is documented proof that we can shift.

I've switched the majority of my caloric intake over to Soylent but I still end up craving meat, for example.

The real problem is the thinking that "it tastes good" trumps all other concerns. Heaven forbid you develop a taste for "man flesh."

1. Soylent is the majority of my caloric intake, so cut out the passive aggressive bullshit I'm trying to make meaningful contributions here.

2. I'm stating the major hurdles that need to be crossed for mainstream adoption. We will not see major shift without an alternative that people want to embrace both ethically and in flavor. Bacon is obsessed over for a reason; people don't want to give that up. We simply won't see a major shift without meat substitutes tasting like meat.