Sure I read somewhere that eggs, meat and dairy consumption worldwide went up by 60 odd % in 20 years from the mid 90's, it's going to take a hell of a change to even halt that never mind reverse it.For the industry it is going to be death by a thousand cuts I'm afraid. Give it ten years and probably most animal production will be commercially unviable given that forecast future trends become only half fulfilled. It only takes a small decrease in underlying demand to make a big difference to commodity prices and profits are only marginal on most farms today.
Yes, the better land may well be converted to arable, but much of the new alternative products are likely to contain very little farm crop. Environmental schemes are likely to be significant income generators for more part time farmers in future.