I bet you read fugly horse of the day, don't you?
If she is truly able to provide a piece of property large enough for them to roam- if she also then gelds all the males so the herd doesn't just keep on growing- and if she's also going to provide all necessary veterinary and other care- then yeah, sure, it's great.
but think about this for a second- 30,000 horses???? Thirty Thousand. She will first need several hundred thousand acres minimum for them to have adequate space to live mostly off the land. They will either need enough space to roam sufficiently to keep their hooves trimmed from natural wear, or they will need literally 100 full-time farriers (I did the math- literally 100) to keep all those hooves trimmed- assuming they can somehow get all these 30,000 horses to cooperate!
Now, let's look at the cost of gelding all those stallions- even if only 1 in 3 is a male, that's still 10,000 stallions to be castrated. At minimum $300 per surgery, that's 3 MILLION DOLLARS just for castration. That doesn't include all the millions of man-hours of effort and follow-up care it would take... we're taking a small army of vets, even if a vet could do 8 castrations a day, which is more than the usual vet can do, it woudl take one vet over 3 1/2 years of working 7 days a week to accomplish it. So she'd need a small army of vets.
if she doesn't plan on castrating them, then she must intend on having round-ups every year to control their numbers, much like the BLM does now- and what exactly is she going to do with all those horses she rounds up? There aren't enough home for all the BLM horses, much less a bunch more from her herd. She could be looking at 10,000 foals a year, or more...
Ultimately, while I think it's noble of her to want to and be willing to do this, the practical aspects of it are impossible. I can only hope that it turns out ok in the end, because it looks to me like a recipe for disaster.