In some idealized world where everyone acts collectively toward the goal of minimising animal production, sure, but that's not actually how it works. If the sup

In some idealized world where everyone acts collectively toward the goal of minimising animal production, sure, but that's not actually how it works. If the supply of fish is constrained, demand for terrestrial animal protein and related land use increases. For arguments sake though, let's grant that all terrestrial food production becomes plant based: adding some well managed fishing would then reduce the land footprint required to produce the calories we need. Some of the ecosystems that have been razed into biodiversity deserts to produce crops won't be needed for agriculture, and can return to wilderness.