One thing that I have not seen mentioned here (maybe I missed it) is that some of the exotics have been saved from extinction by Texas ranching.
Like it or not, it has its benefits.
I have never been that fond of Texas-style hunting, but I am going to hunt Axis does on a 5,000+ acre ranch that is essentially "high fence", although that is a lot of territory for critters to cover.
It will be the first for me, so I will pass judgement afterward!