I would have thought that's all you need in order to be sustainable.We have a septic system so the human waste stays on site and feeds the soil microcosm. It's the driest state on the driest continent in the world here. The city's sewerage is processed and goes back onto farms and has done so for decades.
The king's Highgrove House looks more at ease with nature than Dowding's sample plot.
Some of our young female reporters on TV have faces so made up, with eyelashes, eyes, hair, jewelry, lips and skin so perfect I feel like asking "are you a robot?". I'm guessing that is an outcome of AI. So I'm guessing that the faultless geometry of the public face of no-dig gardening is also because of the computers' 'virtual reality' presentation style. I'm just not convinced that it has the survival gene. It wouldn't last long here. Everything thing is based on irrigation here,
I don't think it matters in the big scheme of things whether you use green manure dug in (sil life recovers in 3 months orso), chop and drop, compost or animals to provide organic matter for your soil. Whether or not you dig; whether or not you use compost or green manures grown in situ - that will make less difference than whether or not you pump your sewage to the local sewage farm or process it on site. If you do the latter you have a closed system that will be sustainable.