Cell culture is very finicky and costly. It&#x27;s profitable when used to produce fancy new antibody drugs like ipilimumab or denosumab, but when it comes to producing meat, the gooey stuff in animals that Westerners won&#x27;t eat do important jobs and are good at them. Tissue culture protocols generally discard the culture medium after a day or two, with barely any of the energetic substrates consumed when too much lactate accumulates, because there is no liver to keep pH balanced. And you need to keep the whole flask drenched with a cocktail of antibiotics because there&#x27;s no spleen doing whatever it is that a spleen does. A chicken gets feed conversion ratio of 2-3 these days in modern factory farming, and I&#x27;ll be impressed if they ever come up with an in vitro system that outperforms that.