> The unfortunate reality is that mankind as we know it, probably developed to the level it did, in part due to the consumption of meat.
Hedging language aside — i.e. "humans evolved because X to some extent" — I recently had an epiphany touring the north island of New Zealand by minibus. Productivity utterly collapses when you have to frequently move from one (temporary) settlement to another. What you eat isn't nearly as impactful as the degree to which you can be stationary.
Interestingly, primitive hunter-gatherer societies could rely upon wild game or fish for caloric intake, which was conducive to a nomadic life. There's no need for an agricultural revolution if you're OK with killing wild animals to harvest their flesh for food. But to call this instrumental in human development is I think wrong. Meat is without question the most primitive way to feed: meat consumption does not require any amount of long-term settlement nor does it require much intelligence: carnivorous animals low in general intelligence regularly kill each other in the wild for food.
Meat consumption is fundamentally a primitive adaptation. Factory farmed meat consumption is a relatively modern phenomenon driven first and foremost by human habituation to the taste of flesh. Plants can provide every nutrient required for human survival save for vitamin B12.
> Meat is absolutely PACKED with bioavailable nutrients in a way that most plant products simply aren't.
Such as? Meat is a euphemism for slabs of fat and muscle tissue containing amino acids. With the exception of wild-caught fatty fish like salmon — factory farmed fatty fish contain greatly reduced levels of omega-3s — the fat is of questionable healthiness compared to vegetable sources. And if you're convinced it's necessary to consume the muscle tissue of formerly living creatures for amino acids, you'd eat insects for environmental sustainability's sake. In fact, insect exoskeletons are a rich source of dietary calcium directly comparable to dairy. The fact most of you reading this wouldn't dream of eating insects, goes to show nutritional value is not why you're eating meat. Taste is #1.
> Add to that, the growing evidence that much of the plant material we're eating may have inflammatory side effects of consumption.
Citation needed.
> The point I am making is that a solution isn't a solution if it means getting rid of one of the most dense forms of nutrition we have.
Where do high-fat nuts and seeds fit in your view of "dense forms of nutrition"? E.g. gram for gram, you're getting much more calories from nuts and seeds than you're getting from low-fat muscle tissue such as chicken.