The titular claim here is demonstrably false.
To be clear, the arguments against the existing meat industry that Jessica Corbett makes are pretty good. It’s just that factory meat and even most traditional systems are not cheap ways of getting meat–at least not in terms of real cost.
With a little help, my rabbits and hens eat the weeds, scraps, and bugs that are products of my garden. When I make some mistake in planning, which does happen, I have to buy some supplementary feed or get scraps from neighbors or local food businesses. The animals, meat included, are now very near to free.
Of course, eating the animals means killing them. So anyone may wish to weigh in about ethically about that. But ideally, that response might include some consideration for the animals killed by removal of habitat by other human farming, since it takes somewhat more land to support a vegan diet than is required for a holistically managed omnivorous diet.
(It does take far less for the vegan diet than for the current factory farming system, by the way; I don’t mean to demonize vegans, who make a compromise that is good and viable in some circumstances).
To generalize, though, less destructive ways of raising food involve having various species, even many species, in one place. In such a system, a fair amount of the living biomass consists of photosynthetic plants, since these are getting the initial energy input from the Sun.
A large percentage of most photosynthetic plants is cellulose–complex sugars, woody or pithy materials. Humans cannot digest such materials, though we get some benefit from eating some of them anyway. However, many other animals, particularly dedicated herbivores, digest them very well. The animals do the general ecosystem a grand favor by converting the product of that cellulose to manure that feeds soil microbes and then the plants.
And humans digest many of these animals reasonably well. Voila–that’s cheap meat. Of course, if you insist on trucking in soy and corn and so forth to feed them, if you keep them wading in manure and shoot them full of antibiotics and chemicals, then they become costly. And of course that describes most of the existing US and international industry.
Allan Savory (holistic management) is very interesting with respect to integrating animals in food systems, as is Bill Mollison (permaculture).