In 2020 (OK, maybe not in 2020 but definetely somwhere in the future) I will be living in a house simmilar to the Philip Johnssons Glass House http://philipjohnsonglasshouse.org/history/
, except it would not be just one block, but few of them intersected and piled upon each other. This will make a room for the rooftop gardens, in which I will grow my own food, letting the vines of the grape-vine slide down the glass walls.
Besides grape-vine, I will grow beans and vegetables there, many of them in hydroponic systems to save up some space. I will also have some fruit trees around the house somwhere. That would keep me supplied as far as vegetables and fruit is concerned. For anything else, I will have to travel to the small town nearby. By bike or bus (in the winter) of course. I will use my electromobile only if really needed. I will also bake my own bread at home (we are doing it daily now, so I dont see why would I need to be dependent on bakeries in the future).
So thats my vision. Nothing special really, just plain old vegetables and fruit, but from my own garden, so that I know, what Im eating and I rely on food suppliers as little as possible.