While I can't "ensure" anything, I would like to see large corporate monoculture farms and CAFOs replaced with smaller, integrated farms, where the farmers use more of a Whole Systems approach to farming. Polyface Farm, while not 100% perfect, is a good example (http://www.polyfacefarms.com/). Truly "grassfed" beef takes almost two years to come to market weight, and is therefore more expensive. Also, the number of animals per square foot of land that can be raised on pasture is much smaller than at a CAFO. We have now both increased the price of meat and reduced the number of available meat animals, while also increasing their lifespan and their quality of life. If meat is both less available and more expensive, people will have little choice but to eat less of it. This style of farming is also less damaging to the environment, and can make use of land that is not suitable for food crops.
Omnivores can certainly thrive without eating meat. I am less convinced that they can remain healthy in the long-term without eating *some* form of animal protein. In terms of animal husbandry, however, keeping animals primarily for milk or egg production will inevitably require culling. Hens stop laying, some chicks will inevitably be roosters, and milk-producing mammals need to give birth at least annually to continue to provide milk. A sustainable farm or homestead can't afford to feed extra mouths or animals who have outlived their usefulness. To my way of thinking, if you are going to need to cull an animal anyway, it is less moral to allow it to go to waste than it is to eat it, even if you do not raise animals for the express purpose of ending up on your dinner plate.