WTF? Have you actually seen an elite boxing match? And any karate guys? It's the exact opposite of what you're saying, literally.
Boxers have the best, craftiest, most efficient footwork in the business - with a lot of lateral movement, pivots, and excellent balance and positioning. Karate guys just move in and out in a straight line, like Wonderboy and Sage.
The idea of Karate being better than boxing is fucking hilarious too. Karate is not a combat sport, most of the sparring and competitions are not even full contact. Karate was the first MA I did as a kid, and it's basically a joke if you actually want to fight, a bit like TKD.
The Karate guys who have had success in the UFC like Wonderboy, have solid kickboxing experience too. The only fighter that looks like a proper karate practitioner and has been highly successful in MMA is Machida, and even Machida trained boxing and MT, just had a strong Karate base and used it to good effect.
An example of how successful pure karate guys would be in MMA is basically Sage.
Cosmo Vs Sage was essentially Boxing Vs Karate. Cosmo used superior footwork, cut off the ring, used feints and superior punching power to decimate Sage with 1 punch.