I'd expect change to come either from stronger regulation of agriculture that makes it much harder to produce meat, or if that's not introduced, from huge food

I'd expect change to come either from stronger regulation of agriculture that makes it much harder to produce meat, or if that's not introduced, from huge food shortages after desertification and other climate change effects become more pronounced. As long as meat is produced in sufficient quantity and at prices consumers can afford, I don't expect huge change from them.