The trouble is getting out and finding it. People don’t have the luxury of window shopping. And after a year or two when people have raided all of the stores and not used their ammo wisely - it’s going to get harder and harder.
I guess the question would be “what is the ratio of zombies to healthy humans?
One box of Walmart .22 is 500 rounds. Zombies seem to move slowly. With a .22 rifle and scope, you can easily make headshots at 50 yards, and .22 silencers are easy to make.
I would think a zombie hunting party could take down thousands relatively easily, and once you clear off a fair sized island, where are more zombies going to come from?
It also seems that there would be lots of boats available that you could live on safely.
I have never heard of zombies swimming.
I agree, it is a fantasy about warfare where the enemy is numerous but stupid and armed with primitive weapons. Kind of a gamer Valhalla.