But deep fried, richly seasoned mushrooms pair so well with steak and a cigar...

Why do you say that a vegetarian/vegan population is a fantasy?

Meat isn't required. We could all be vegetarian.

The impact to quality of life could be minimal. Right now, today, there exist plant-based burgers (Beyond) and even steaks (Juicy Marbles) that are in every way superior to the average offal-based "meat" you get from the average fast food joint. Granted that you can't replicate the very nicest of fine cuts with plants - yet - but how often are you really eating rare sirloin for lunch anyway? Right now the plant based alternatives are more expensive than animal meats, but this is an economic artifact that would evaporate in a hypothetical world where meat consumption was de-normalized (and meat subsidies halted!).

Perhaps you mean it's counterfactual because you don't think it's a social norm that has a hope of being challenged. I think that's defeatist. Vegetarianism is practiced globally. You must begin from the following perspective: this is an indulgence, not a necessity for survival or even a requirement for a happy life. Raising an entire animal only to slaughter it for consumption is wanton extravagance of both physical and moral resource. Its practitioners deserve no subsidy, financial or social. Most people would be quite put off their meat if forced to viscerally confront the reality, but are carefully insulated from it - usually by simple distance and pleasant marketing, but in some places by actual legislation: https://en.wikipedia.org/wiki/Ag-gag

In short, like most of the evils of world today, it's not a necessary evil. Just a lazy, can't-be-bothered-to-change, would-upset-the-current-economic-order evil.

There's a wide range between factory farming and vegetarianism. Moderate, humane farming and lower-but-not-zero meat consumption is a perfectly realistic alternative to the extremes.

> required

Source? Keep in mind factory farms are subsidized by corn subsidies (used for feed) and by not paying for externalities, namely the antibiotic-resistance they breed due to their overuse of medication to keep animals alive in such oppressive environments. Antibiotic-resistant bacteria are a far greater threat to that world of 8 billion people than slightly higher meat prices.

> counterfactual fantasy

20-40% of India is vegetarian, and factory farms barely existed before the 1950s, and become widespread even later. Far from a fantasy, it did and does work.

There's nothing lazier than looking at a system, and declaring, without evidence, that no other way could work. Especially when there are counterexamples in living memory.