People can live without meat, with the right supplements. Its not easy to transition into that life but its possible.
That's what most vegetarians I know use an argument. It seems to be pretty infallible, too.

Better food more room to move around but is that enough?
The truth is, the meat industry (and dairy industry by extension) are not concerned with the lives of their animals, but rather the amount of $$$ they can churn out. At the end of the day, these animal's lives are still being cut short in some way, and so it'd still be deemed unethical by some. The only way I can see meat eating to be ethical if it was a) artificially produced in a laboratory or b) the animal died of natural causes, but both have problems. The former is expensive and technologically difficult, and the latter poses health risks and poorer quality meat. There may never be a clear cut answer that will satisfy everyone.