A percentage of people (unknown but high) "don't care about living in extreme zones" for the same reason people in real life live along rivers and coastal areas --It makes life easier and is much more practical for survival. The people who do live out in extreme zones are probably going to be MUCH more self sufficient by nature.
A total exaggeration. Like thurgond said, you still have to travel out to said person to make your deal and then deathport home. This is a time saver when you are, for instance, hauling a full bin of granite that with or without a cart you are moving in utter slow motion. In a game that requires you to grind MASSIVE amounts of items endlessly removing some kind of short cuts, albeit with a penalty or not, will also lose players who just will not be willing to put up with the undue time/energy that is required to 'play' the game.
This regional resource distribution you talk about has very minimal impact on the game. No one cares what kind of plates or nails or whatnot they have unless they intend to make a very specific high level crafted item which by my estimation does not happen all that often. One reason is because some of those items are beyond rare. Where is the tribe sitting on these resources and selling them to great profit? Anyone...anyone?
Hire a hundred chinamen (apologies to those from the orient. I did not invent exploitation and don't support it.) working 60 hours a week and you might have something. Short of that maybe it is not supportable? But lets force people to do it anyway..?
Where do I sign up?