Gail asked "And what does permaculture suggest that we do with all of the agri-businesses that now own so much of the land.  Does it address that?"

Their requirements suggest that agri-businesses will retreat or collapse, as the costs of fuels used throughout the big (etc.) food system and of acquiring and processing raw materials used for fertilization and control of weeds and pests escalate.  When they do, eroded/depleted/vacated lands may become available to a new generation of producers.  On the other hand, Monsanto is (providing the service of) preparing for a world of 16 billion people, so what will happen is anybody's guess... or project.

Permaculture practitioners with whom I'm most familiar anticipate a society learning how to power down, including taking over and bringing home productive work that has been done lately by energy slaves and migrant workers.  This will involve productive activities, not necessarily identical to those that had been delegated to other, sometimes distant, regions; permaculture instead of industrial ag.

Permaculture arrived timely, but gained acceptance perhaps too slowly/late.  Soon after it premiered, Wozniak, Jobs et al introduced a distraction that still has a lot of the attention of many (almost all of us), though it doesn't arrange to produce food, fuel or fibers.  And that's just one reason most of us tend to stay indoors, away from soils.