Jarrod's permaculture project seemed to mostly involve a bunch of fruit, vegetable and herb seeds, some of which stood a chance in the growing season (chard, spinach, thyme) and some which definitely did not (cantaloupes, butternut squash). I don't think we ever saw him plant them.
In order to have any chance he would have needed to grow them in containers or in raised beds filled with fertile topsoil and lined with wood (like a bootleg hugelkultur) but container gardening doesn't feel very permaculture and he'd have needed a bunch of time, money and resources to get all the soil, wood etc for efficient raised beds. Also even with hugelkultur he probably would have had to water the shit out of it, which isn't very permaculture. And between the field serfs leaving and Penny starting up his terrible construction company, there probably hasn't been much spare time or money (or energy) for something that ambitious.
I think the concept of growing feedstock probably didn't really occur to him, because it's less tangible compared to foraging in the forest or having delicious home grown veg on the table.
I'm trying to think how you could even try and salvage some of that land - I'm no farmer but I do garden. You'd probably need to hire a rotorvator or plough because there's too much ground to get in there with a garden fork. Plough the alpaca manure into the soil and then immediately lay down loads of rolls of turf and water the shit out of it for weeks in the hopes it roots and stops loose soil blowing away. Then I guess get planting actual feedstock, and keep the livestock away from it for a couple years while you work on other patches and then set up a system of rotating grazing?
I don't know if that would even work given the climate extremes and amount of water they have access to (and the fact the alpaca would probably manage to get in, or be lead in by Penny who would want photos of them in a temporarily verdant landscape). Even if it did work, I imagine the cost would be astronomical, and given none of them own the Tranch, they'd probably see it as just furnishing Bonnie's pocket.