I would agree. The challenge is that, for many species being brought into captivity for the first time, there can be high mortality in those early days. Part of it will be due to the likely compromised health of animals brought in from the wild, to say nothing of potential injuries and stress from their transport. Part of it will be due to insufficient knowledge of their husbandry requirements to provide optimal care and promote reproduction. Those hurdles have been overcome with many other species in the past - gorillas used to be considered impossible to keep alive, now they are abundant in zoos. The issue is that ethics and societal perceptions have changed, and losing large numbers of animals while we tinker around with the parameters of their care would no longer be considered acceptable by many people, unless the conservation status of that species in the wild leaves us with no other choice.
You'd mentioned Ethiopian wolves in a different thread. I have no doubt that, if a sufficiently large number of Ethiopian wolves had been exported to Europe and North America one hundred years ago, we'd have them with us in zoos today.
