Earlier quoted context omitted.
Problem is how many people really care enough to do much about it?
I think it's more brutal than that. How many humans are we willing to kill (or watch them die) in order to do much about it? Most humans care some about animals, but they care more about humans. (Yes, I am well aware that the developed world could accept a lower standard of living, and that would help. I question whether it's enough. And yes, I am aware that that is not an excuse for the developed world to do nothing…
Fortunately, the human growth rate is stabilizing so hopefully we can figure out how to have humans grow to a natural equilibrium AND keep diverse ecosystem. If the question is framed as either humans or animals, society will end up with only zoos, farms, and humans.