There's a lot to learn and practice to achieve mastery in those games. And experience in other similar video games will strongly correlate to how quick and high the skill in one particular (popular) game will be achieved.
I was watching a video a while back with these two guys playing QuakeIII. They both knew the map intimately, and kept track of when power-ups would respawn based on when they were picked up. Then they based their strategy on what resources they had, and what resources their opponent had and where the other was likely to go next.
So yeah, we're talking hundreds, if not thousands of hours devoted to mastery in this game. Against an opponent like that, two Quake newbies would score about the same (dying almost instantly), even if one of the newbies was otherwise very smart, and the other very dumb.