I read his book, and follow a lot of his videos. I grew up on a farm in Southern Saskatchewan, and work there seasonally when I'm not in University. Because of this, I have a bit of an inside perspective on the monocropping world of farming. From all that I know from my experience, Mark Shepards model is an excellent idea. I hope to implement it myself on my land with my own local biome one day. His analysis of the issues with monocropping agriculture is dead on, and even my family who participates in it would agree with most of his criticisms (though I haven't introduced them to his work directly since they'd be turned off by the hippy-ishness of permaculture lol). Subsoil plowing, silvopasture, alley cropping, keyline design and water harvesting, the benefits of perennials vs. annuals, and the destruction that tillage and insecticides cause are all things that my family find compelling. And mind you, they are not organic farmers. They consider each of these things to have potential and to be economically viable, but they have a "believe it when they see it" mindset towards these things.
So yes, there's good reason to have faith in Mark Shepard's model. I believe in it so much I want to try it myself. But I think the reason not many people have adopted it is because 1. it's not well known outside permaculture circles and 2. "hippy" type ideas like this are hard to sell to farmers who are deeply conservative and distrusting towards leftist political types and environmentalists, so to get them to even consider it's viability is a challenge and 3. Farmland is extremely expensive, and to try farming on even Mark Shepard's scale would take a huge loan that would be hard to pay off, and I think that's too daunting for many people to give it a try.
