That's probably a good idea, but it's worth noting that about 30% of the Earth's land surface is too dry for crops, but works fine for pasturing cattle.
Take for instance the factory farms which have to constantly ship food in to feed the cattle. Another example is deforestation to create fields for cattle to graze.
I think the OP is right, we need to convince more people that beef is not a sustainable food with the rate at which we consume it today.
People probably wouldn't eat as much meat as they do now if it were from free range, non-grain fed animals.