For sure it does. Let us look at some well known pro-fighters with TMA backgrounds that compete successfully in MMA: Georges St. Pierre - UFC welterweight champion (Kyokushin Karate), Lyoto Machida - UFC light heavyweight contender and former champion (Shotokan Karate),
and Cung Le - Strikeforce middleweight contender and former champion (San Shou Kung-fu).
MMA as we know it today is in fact a style in and of itself. It consists of stand-up striking (boxing and various forms of kickboxing), grappling (wrestling, judo, shuai jiao, etc), and ground submissions (BJJ, sambo, etc).
Of course each of the mentioned fighters are well versed in all the aspects of MMA but also that they have a solid base in their respective TMA, they can utilize their styles and techniques to bring something “different” to the fight game and capitalize on it.
So what does this mean? Simply put, learning other arts/styles does not dilute or taint YOUR art. In fact it goes to enhance it as you become familiar with the opponents arsenal while formulating how to effectively employ your skills.
At the end of the day be open minded, learn new things, think outside the box, and in turn you will grow and adapt as a martial artist. Just like all life must – evolve.