There really must be a balance. We are depicting a modern world, with an abundance of prefab food laying around. If we depopulate an area, lets say for instance the suburb outside of Stockholm (Sweden) where I live, and we do it very fast with a zombie infection, I am quite sure that there would be plenty of canned/dryed and other means of preserved food around, for quite some time. Also common medications, like bandages, bandaids, penecilin etc. However, it will, naturally decrease in number during time. But still, an area as large as this would provide for me and quite few others for a long time. Gas stations would have gasoline and other other necessities for keeping vehicles running and so forth.
Even if I, lets say, after quite some time, had to move out in a rural area, there would still be stuff around, more than you would think I belive.
I am not against the survival aspect, on the contrary, but we need to give it time, let the devs work and tweak the system, work on tools for us to use. As allways, remember that this is a game in development, and I forsee (insert Emperors voice) a rather good future for this game, with a nice and balanced (game play wise, so it doesn't turn in to a farming sim) system where you forage and farm/hunt in a team work oriented way.