A cow's rumen is amazing. You can feed a cow almost any vegetable matter and they will grow and produce milk and meat. Chickens and pigs are more particular but in terms of energy in to food out, are still very inexpensive and easy to manage. Cell cultures require sterile laboratory conditions, growth factors and very specific nutrient requirements.
A largely plant-based diet, sure, that is what most (but not all) of our hunter gatherer ancestors ate, but I doubt cell cultures will ever get within even a order of magnitude of the efficiency of growing and eating real animals.
But animals spend a lot of energy making products other than consumable protein. They require a lot of land and water and fuel even if housed in close quarters. And you have to tend them which is labor intensive. And ship them around to be finished and slaughtered.
If energy costs rise to a certain point and technology becomes good enough (including automation) I'd expect protein from whole animals to be considerably more expensive than lab grown.
The exception maybe being strictly grass fed beef on land that isn't useful for much else. But that won't have the taste people expect and might not actually be as good as the lab grown stuff.
A cow's rumen is amazing. You can feed a cow almost any vegetable matter and they will grow and produce milk and meat. Chickens and pigs are more particular but in terms of energy in to food out, are still very inexpensive and easy to manage. Cell cultures require sterile laboratory conditions, growth factors and very specific nutrient requirements.
A largely plant-based diet, sure, that is what most (but not all) of our hunter gatherer ancestors ate, but I doubt cell cultures will ever get within even a order of magnitude of the efficiency of growing and eating real animals.