As a generalisation, the Americans are rubbish at making after-the-apocalypse stories, whereas the Poms are great at it. I speculate wildly that this relates to the stages those two empires are at. Only one is able to acknowledge they could fall.
Walking Dead is probably a better example of a Yank attempt at it. It also happens to be a great example of how to make all characters both un-likeable and un-interesting, and have said characters be insanely stupid to create drama. Worse, the show-makers seems to have assumed they can get away with that, on the basis that the watchers are treated as morons too.
(I didn't get past the first episode of the second season, which includes such classic scenes as the one where the look-out on top of the caravan with the binoculars fails to see a couple hundred zombies coming down the highway until they're fifty metres away.)