This is not the first time this subject has been beat on, here. But, as usual, there's a lot of misunderstanding.
A "canned hunt" is where a game animal is confined to an area so small that it cannot escape a hunter. Okay? That has zilch to do with 99% of the high-fence hunting ranches.
For a high percentage of the high-fence ranch, the fence is to keep other deer OUT. Improved pasture or a re-growth of native grasses, herbs and forbs is attractive to other deer besides the residents, and can wind up with over-use of the habitat.
The majority of such ranches in Texas are for whitetail. A whitetail basically lives in--is imprinted by--about a section of land. 640 acres. The hunting pastures on such ranches are commonly well above a thousand acres. Since many are mixed-use with cattle, the interior fencing of a 10K or 20K ranch is commonly "normal" height and are easily jumped by a deer.
Next is the typical vegetation: Beaucoup brush. In much of it, a deer would have to stand on his hind legs and wave in order to be seen. IOW, just finding a deer can be a serious challenge, even within small areas in a pasture.
For the walking hunters among us: How many acres of brushy country do you think you can work out and really hunt, in a day? I'm not talking about open grassland country.
I've hunted in the Appalachicola River bottomland below Blountstown, FL, and sitting is far more practical than walking, although skillful sneaky-snaking can be productive. Same in timber country east of Tallahassee. Same behind my wife's house on the upper Ochlocknee River in Jawgia. But I'm a helluva lot better at sneaky-snaking than most folks, since I grew up doing just that from about age six or seven.
Terlingua? Ehhh...Ten to twelve miles in a day has been common. My favorite quail-hunt trek is three miles, one way. Here, if you can't kill a running deer at 300 or 400 yards, you may well not get another chance, all season.
Bottom line? Don't form an opinion when the knowledge isn't there. There is no such thing as "One size fits all," in what's right and proper in hunting.