I don't buy this argument. The treatment of each individual animal should be seen as important. An individual cow isn't really going to have a better life just because it's species as a whole is doing better globally.
Something else to consider. Let's use cows for this. If we all stopped eating beef, drinking milk, making things from leather and so on, what would actually happen to cows as a species? Outside of India they'd go fucking extinct in no time at all. They only exist because we find them useful. Perhaps we treat them cruelly, but if we didn't use them they wouldn't even exist.