Prolly too much of a socio-political hot potato to expect objective analysis. But the fact remains (and without getting into the associated developments), H. Sapiens only became dominant over the other apes after it adopted hunting as a lifestyle.
I'm not saying healthy vegetarianism can't be done (veganism is too stupid in concept to bother addressing) but it takes strategy and careful balancing of diet, and an extra layer of monitoring from your health care professional. And unless you grow your own, it can be pretty spendy. Which puts it beyond the fiscal and intellectual means of the majority of the hoopleheads who've jumped on the vegetarian bandwagon because it makes them popular with their peeps.
Those are the people who have volunteered to be progenitors to generations of the dietarily retarded.
You just said what I was thinking about a vegetarian diet. It can be done and it can be nutritionally balanced and very tasty.
But it is expensive, time consuming and requires a serious commitment to nutritional education, monitoring of meals and top notch cooking skills. As a gardener I’d say that would also be expensive to do to grow and preserve everything you’d need.
And, as you say, all that is probably not enough so as to need regular blood work etc. to be sure you were on track.
It’s not workable for the lazy or those with time constraints imposed by work or leisure time activities.