That's disingenuous.
From 1940 to 2010 Texas played 807 games while Oklahoma played 809.
Texas win percentage: 71.6%
Oklahoma win percentage: 74.1%
Purely from a mathematical standpoint, 2.5 percentage points is not what I would consider that much statistical significance.
In those 71 years, Texas and Oklahoma have played every year. Texas won 38 of the match-ups, Oklahoma won 30, and there were 3 ties.
So, again, show me where Oklahoma has had "so much more success" than Texas.
I would consider it a tie. Which is why the rivalry is always so good every year.