It is logic, not archaeology, which claims the vegetable garden as the oldest of all garden types. Homo sapiens began as hunter gather, roaming Africa. We settled for the purpose of tending crops. This probably began with wild grain. Cerals benefit from an enclosure but can be protected from grazing animals by men and dogs. But for growing vegetables an enclosure have significant advantages: the wall keeps out beasts, fellow humans, cold winds and weed seeds.
The brave individuals who continue to grow their own vegetables are in noblest tradition and deserve more support than they normally receive from society.