Your looking at it from the wrong perspective. A lot of the people that do a Super Exotic hunt in Texas don't have the time to take a 7 to 10 day hunt. It's a different product for a different market. It's not a coincidence, that a lot of ranches that have Super Exotics, cater to a corporate clientele.
I agree with the above quote
I've been to Africa twice and plan on going again. But there are African animals here in Texas that I just don't think I will ever be able to hunt in Africa. Grants Gazelle is one of them. They are here in Texas, and in my opinion, it would be cheaper to shoot one here then to go to Tanzania to get one. Sable is another. I've seen deals where a Sable has hurt itself, or something has happened that it's cheaper to shoot one here in Texas then to fly to Africa to get one. I' hoping to get mine in Africa, but if a deal comes along, I might be willing to rethink that.
As for Blesbok, I found them to be one of the most clueless animals that I've ever come across. They let you get close, they don't run off, they bunch up together. Then it's just a waiting game until the biggest one steps away from the others for a clear shot. They are cheap in Africa, and it's something different on the wall that doesn't look like anything else, so it's nice to have.