I think in some cases such as in the first example that the original english white terrier can be somewhat "revived" from extinction in some form. I think when the English brought their english white terrier dogs to Pakistan it has somewhat still remained in function while crossing their dogs with it and coming with the closely type and functional gull terr. This dog is still an avid hunter in Pakistan. I think it would be even further close to the original English white terrier if it was bred with America's EBT maybe.