That is why I don't like them and usually ignore them. It is like I'm in the apocalypse, but wait there is a Walmart.
I'd prefer they were gated somehow, like on day one they don't trust you and rip you off. Over time they get to know you and give you more reasonable deals.
I fully agree. However, speaking of the out-of-place traders, I'd love for this pipe-dream (for 7days version 1, anyway) to happen:
You have 'The Duke' who has established himself the boss, simply because he's the richest, but not necessarily the most moral. In fact, his morals are probably very lacking. For example, he is the one who allows the bandits, and even employs them, to do his bidding.
Then you have traders, again, they need to give a percentage to the Duke or the bandits end up intervening.
The zombies are merely a by-product of something gone wrong or maybe the Duke has found a way to extinguish all that is not under his control (and uses the zombies as cheap labor to do it).
Now as for you, as the game has it now, you are a zombie that somehow fought off the effects of whatever the Duke did to you. However, you can also choose (at the start or at death) to be either a trader or a bandit. Both of these have their benefits to adding to the storyline.
As a trader, you are posted, by the Duke to run the shop. So fixing it up after Z's damage it, maintain it, scavenge for useful things near the compound, serve bandits and NPC's. However if you don't pay him his money or if you give up the life of a trader to become an explorer (so leave the compound unmanned), he will send his bandits after you.
If you want to be a bandit, there are certain jobs that get you higher and higher privileges and weapons, etc, and you can overthrow the Duke eventually. Or your faction of the bandits can be very loyal and just terrorize the neighbourhood.
That has something everyone wants. A sandbox game with almost no story (current game-play). A responsibility within the game with orders and decisions to make. Or hunger for story and power as a bandit.