This is, unfortunately, one of the fallacies of the hobby that is often used for improper justification for wild-collection.
Yes, captive populations can help preserve the genetic identity of an animal species if the habitat were obliterated. That said, the captive populations in the hobby could never be released into the wild because of the way the hobby breeds things. There is zero thought given to genetic diversity and maintaining a broad and healthy represented population. Actual SSPs have to go to some very extreme measures when they are working toward reintroduction populations