Texas still has two teams which rule their respective market. The Cowboys rule much of the country (and of course overshadow the Stars, Rangers, and Mavs). The Texans by far rule Houston as well (Rockets and Astros fall short).
Sort of back on topic, but we're a bit premature to say we're going to pass the Cubs on the field. As far as off the field, the Cubs will always have a bigger fanbase, but they're so damn fickle and uninterested in baseball as a whole that the White Sox fanbase is just so much more concentrated and interesting when the team is good.