On the other hand fishermen do not discard so many small fishes as previously. Our cats and dogs will eat that.
"ending factory farming as soon as possible" equals at this moment to "killing by famine a lot of surplus humans as soon as possible". We need to produce more food, not less, because we are more people than the year before, not less.
The article is talking about animal factory farming. Eliminating animal factory farming would free up more than enough resources to feed humans directly. The conversion from plant calories to meat calories is not very efficient.
Animals in animal factory farming can be feeded with things that neither humans nor plants can/would accept directly.
Animal factory farming by-products also are needed to support agriculture. Using human faeces at large scale to fertilize the spoil is not so good idea as using horse, goat, cow or pig faeces (Because human faeces carry more types of human transmisible parasites and more often than faeces in non-human animals).
Agriculture without using fertilizers will not provide the same harvests.
We have only one planet and the only land available yet to put all this cattle (that is apt to breed cattle and not used yet) are the last sanctuaries of biodiversity. We will need to burn the forests if we want to scalate our solution of "freedom for all cows and pigs".
Therefore we must be aware that our shiny plan of liberating resources to feed humans could backfire easily in several parts.
There is not a morally-magic solution for our current problems (and we have big problems). Meat generated in lab will need also resources to grow. We talk about chemical resources, lots of water, sterilization material and lots of energy. And currently is just a very expensive way with the main purpose to provide vegans with a exit way to lie to themselves and eat meat that "is not meat, just a nerveless animal tissue thin as a paper".