Is this true? I was always under the impression that meat was considerably more expensive than basic vegetarian food. I know some vegetables can be expensive but I'm pretty sure cereals and pulses are cheaper than any meat.
While this book is interesting it seems to go to great lengths to create new dishes when many compatible traditional dishes exist. For example you can make Schnitzel, Spaetzle, Blaukraut and Brussel sprouts for 5 for around $10.
Of course mince meat is cheaper per calorie than lettuce, it's probably cheaper than tomatoes, but it's not cheaper than rice or lentils.
BTW - I live in Europe too.
Back in my old days in post communist Europe, the cheapest eatable meat was horse (kind of like a beef). Most vegetables were imported (and expensive) or scarce outside of season (and expensive) . People usually loaded their cellars with 1000 pounds of vegs for winter, but students did not had this option.
Dried beans (my favorite) tend to be much cheaper than just about any other source of protein, but I don't think I've ever seen tofu being sold for less than hamburger. Ground meat in this country tends to be really cheap, thanks to agricultural subsidies, filler, "pink slime" and the like.
In terms of calories, this is technically correct, but the metric of calories is not at all useful in a first-world context. At my local market, £1 gets you about 10,000 kcals of rice or pasta. In other words, any budget above $1 / £1 per day will be able to provide plenty of kcals. Kcals are not the problem.
What matters are the other things the body needs. I eat vegetables to provide fiber, vitamins and phytonutrients. I eat meat to provide protein and certain types of fat. In this regard, they're not fungible, because leafy green vegetables are a poor source of protein and meat is a poor source of phytonutrients.