Maybe because the problem is arising people will move to short urls on their own sites so that they don't even need to be shortened for twitter and such, because honestly the problem isn't that the urls are redirecting its that the urls need to be redirected because of an unnecessary long url for clarity.

In all honesty I don't know very many people that look at the full url before they click on it; the domain name does most of the work and the description accompanying the url does the rest.