This wasn't always widely available, especially during the Great Depression. And, it didn't solve the issue of babies who couldn't tolerate cow's milk at all. My great grandmother had two babies she wasn't able to adequately feed by breastfeeding. They starved to death at her breast. The second time she was suffering this issue, my great grandfather traveled two days to reach the nearest place he might buy evaporated milk. Unfortunately, by the time he returned home, that second baby had died.