You are correct that producing animals requires much higher more stuff. But that wasn't my point. You could have substituted your argument for producing more veggies in place of mine for producing more veggies. The result would be the same. We still have to produce the infrastructure to manage the change. And that infrastructure is complicated, expensive, and requires a lot of technologies. Anyhow, I doubt we could eliminate raising animals in place of veggies because animal products are used in a lot more than just food. You'll be wanting to replace all those too. That will require more tech, start now, time's awasting...
My point was that in order to fail to consume all that Ashton wishes us to fail to consume, he has no way to get from here to there. We get in the way because we want too many things. We even want the things that will allow us to consume less, and have to produce those things, thus starting the cycle all over again.
But I do not think it is a zero sum game. We can consume less, but we won't get there by attempting to change human nature, we'll get there because we've learned how to become more efficient and do it in such a way that we would want to do it.