In this case the wine is being sold directly to restaurants, removing any middlemen. The pigs are being made into artisanal chorizo onsite, and direct-to-consumer sales allows the farmer to capture most of the markup. Similar goes for the market gardener selling fresh and washed vegetables directly at markets and to CSA box subscribers.

I'm not suggesting everyone can be Jean-Martin Fortier, but with sufficiently low overheads and access to somewhat affluent markets, it is possible to make a living on an acre.