I believe that one aspect of the necessary change is repopulation of the countryside. Large-scale energy-intensive mechanised farming is incompatible with permaculture principles. And the key to sustainable food production from the land together with biodiversity is design-intensive and human-attention-intensive production. Doing this on an isolated farm or smallholding may provide earth care but it does not mean satisfactory people care, which requires a thriving community in the countryside.
To be sustainable, the countryside needs to have communities within it the majority of whose populations do not need to frequently travel significant distances and who can spend most of their time at home.
Co-housing eco-hamlets can be part of a truly sustainable countryside when they integrate into the surrounding community and incorporate small scale manufacturing for local needs, people working at home with the aid of the internet and possibly providing employment for others in the community.