Dallas has never been particularly friendly to sports franchises. I think Ron Kirk helped the Mavs, but before and after him, the city weren't interested in playing ball with the owners. Unfortunately for the Rangers, the Ron Kirk era didn't start til a couple years after they committed to Arlington.
So, hopefully we see the end of the "Why the Rangers should be in Dallas" posts that pop up from time to time. Quite simply, Arlington has always been willing to play ball, and view getting sports and entertainment facilities as part of their economic development, Dallas isn't interested.