[conjectures]

"Animal farming is not the most efficient way to provide calories, but humanity does not lack for calories."

Actually, a lot of humans do go hungry. The inefficiency of using land for crops to feed to livestock means that the price of staples is higher than it otherwise would be.

While meeting market demands is a large part of what will change things I think you're missing a piece on how this will come about. If there were no vegans, the chance of vegan unicorns succeeding would be much smaller. If some people did not harp on about the inhumanity of industrial farming, others would be less motivated to try alternatives and the chance of vegan unicorns succeeding would be reduced.

[DuskStar]

> Actually, a lot of humans do go hungry. The inefficiency of using land for crops to feed to livestock means that the price of staples is higher than it otherwise would be.

I'll posit that even if you made grain free at the docks in the US, there would still be people in the world going hungry. (Fewer people, certainly) Transportation and distribution is just as large a problem as production at this point in history.