Because it's even more ridiculous than raising normal animals for food. Producing a whole animal minus a functional brain is no less wasteful than raising a normal animal and you have the added expense of developing this tech (which, granted, goes to zero with time). We can already grow meat without actual animals, just using animal cells, and even engineering meat from completely plant tissue is viable. And that's for the case someone is psychologically “desperate” for meat as such, because we don't really need any animal products in our diet.

it is. it's a stupid idea.

although, when I go vegan, I don't like taking supplements. If we could engineer some foods to provide all the B12, Zinc & Iron etc we need that are hard to get from vegetables (without a a lot of effort) that would be nice.

We already do that, kind of, again in an extremely wasteful manner. Farmed animals get their B12 from supplementation mostly, so pretty much both vegans and non-vegans get it from supplementation. The food in the supply chain for both humans and farmed animals is just way to clean (good!) to get enough B12 without supplementation. I'm guessing that B12 is not the only micronutrient that is supplemented. But seriously, apart from B12, if one has any semblance of a reasonable, moderately varied diet, micros are not an issue in a vegan diet, you can easily verify this on nutrition trackers. And if you don't you probably should take some supplementation anyway.

Why not just isolate the meat and just grow meat? instead of growing lambs without brains that still have to grow into adults just to waste bones/tenonds/all other non edibles etc. etc. etc.

This is coming soon; there's already companies working on this. It makes the most sense, because once you can grow stuff biologically, for meat you only want the muscle and fat, you don't want the rest, so why bother growing it?

I predict that within 50 years (which may be overly conservative), killing animals for meat will be all but extinct, and we'll be eating artificially-grown meat.

I think (in the absence of any post-school biology qualifications) that most of the rest is necessary to keep it alive. Bones make the blood, the white blood cells stop every random infection consuming the flesh they way they make it rot when it's dead.

As a meat-eater, I'd welcome that. It would be a great way to step around the whole issue of animal suffering.

Wouldn't such technology be forever rooted in animal suffering?

That is, I sort of doubt that the first attempts are 100% successful.

I don't mind really; I don't see how developing it would involve more animal suffering than normal breeding of animals for slaughter.

or, going the other way, it reminds me of a Stephen Baxter novel where humans were exclusively fed by "mummy cows", which were genetically-engineered cows who could provide meat while staying alive and actually enjoyed having meat taken from their bodies

Wait, wasn't this a joke in Douglas Adams's Restaurant at the End of the Universe?

I'm probably conflating the two

was thinking that too. Isn't there already a genetic condition where mammals can be born with no brain ? If so, CRISPR that up and there you go -- suffering-free meat in a convenient boil-in-the-bag format

There is, anencephaly, but it normally causes stillbirths in humans.