While I agree that 30mins per week does not go far enough to "maintain " a ten rod plot, probably by a factor of ten !, since I have shared a communal garden of several plots, I have been amazed at the choice of priority re tasking practiced by others.
Rather than cultivate they scratch about ,much like hens and scatter seeds into the wind. Some have "runways" of old boards on which to dance, others seem to only plant the patches they can lean over to reach. Many have the time to plant , but not the time to hoe, or pick their crops. Slugs are allowed free reign, beans are allowed a few strings between canes, raspberries and strawbs grown , it seems, just for the birds. Compost bins are filled but never emptied. The concept of adding manure, an alien art. Still its the "freedom " that does one good........