Quorn (an excellent vegetarian meat alternative grown from a fungus) has been around since the 1980's, and is at price parity with animal ground beef. It has never been more popular than animal meat. Seitan made from vital wheat gluten at home is $1.80 a pound, and can replicate a side of ham, beef, or roast chicken with different flavorings. It is not popular among non-vegetarians or vegans in the west, even the impoverished, despite its low cost. The most expensive Tofu is cheaper than ground beef with comparable protein content, and can be an excellent tasting alternative. Lentils can fill in for ground beef (though not comparable in taste to meat alternatives) and provide far more protein content per dollar than ground beef can provide.

I agree that factory farming combined with subsidies are artificially making animal meat affordable enough for mass adoption, and that if those practices were ended, people would be forced to switch away from it as a main source of food. This is a similar quandary to gasoline.

But even with those subsidies, there are vegetarian options that are currently cheaper than real meat, yet are not chosen by the consumer.

The issue is not purely economics, but cultural. People could, right now, choose the cheaper, healthier, ethical, and environmental option, but they do not. Another user here in this thread literally told me they would not consider switching away from meat because the alternatives were not perfect replacements, and were not inclined to try impossible even after being informed it has advanced to be a 1-to-1 replacement. It was not economic. In their own words:

"Meat is delicious. We’ve been eating meat as long as the human race existed and I don’t think there is anything you can say or do that would get the majority of the population to give it up. I don’t think it’s an identical product and am unlikely to switch. There is nothing I enjoy eating more than a prime rib, and there just isn’t going to be a plant based replacement for that."

Consider that the wealthier people in the world could afford to choose a slightly more expensive meat alternative, but they do not. The middle class can afford a slightly more expensive meat alternative, they do not. The poor could opt for cheaper plant meat alternatives, they do not. Anyone could choose to simply eat less meat, or cut out red meat at the very least (the most emissions) in favor of chicken or fish, but they do not.

Demand for red meat increases with the economic wealth of a nation. Only India bucks that trend somewhat due to having a culture of vegetarianism. My point is that despite having access to viable alternatives, even if made so similarly that it is hard to tell the difference, people choose not to adopt them, even though a collective consumer choice would drastically help our chances at surviving climate change.