I agree. And there is a lot of calls for it on the official forums.
Ascaron say they considered it very carefully and decided against it. I'm not sure why. Probably because of balance. You could turn Lv. 200 characters into pure bargainers or blacksmithers and pimp out your other characters and/or sell the stuff you buy/make, for example. And if everyone done that, nothing would be valuable. --- I get no sleep.