Seconded.
Like any physical endeavor, the individual talents, proclivities, innate physical gifts of the person trying to achieve skill play a huge part. Some guys do better at basketball vs. football.
Or perhaps more to the accurately: some guys do better at the 400, the 800, the long jump, the hurdle, the pole vault...or some do better at the pommel horse vs. the rings, uneven bars, parallel bars, or floor routine. You can go out for track and field or gymnastics, and be great at some facets but not others.
Hence, some guys take to Karate, some to TKD, some to Muay Thai.
Instruction is another factor; obviously, you'll never master a style if the teaching sucks ass. This may be wholly independent of how good the teacher is, as many elite athletes quite simply fail miserably when it comes to conveying the secrets to the success to a novice.
And sometimes, your success depends on how well your learning style meshes with the teaching style of your instructor/coach. Some guys like to be ridden hard and pushed relentltessly, some prefer to be mentored. Sometimes, you may struggle futilely mastering a technqiue or hit a plateau in performance where it seems you will never get beyond a certain point when another coach with a different angle or take on training can show you a way you can assimilate better (I've seen it happen, it does quite a bit).