Societal change (down to the individual level) is the only thing that's going to work. People will have to change how they live and make different decisions. Full stop. There's no magic solution waiting to be discovered.

Whether the change comes voluntarily or through war, famine, and misery for future generations the likes of which we can't imagine is up to those of us alive today.

Behavior change is completely necessary if you want societal change. If you reduce the supply of meat/oil with policy without reducing demand, it would increase prices and people would protest, so we'd be back at square one.