Well yes and no. Obviously for most things you will get better with practise but it's certainly also true that you are genetically predisposed to learn some things faster than others and be able to get to a higher level quicker and have a higher chance of becoming one of the best in that field. So it makes sense to specialise in those things.
For example I'm sure I could run pretty fast if I trained but I'm never going to beat the 100m record because I'm not usain bolt.
That's sort of a positive feedback loop, if you find yourself doing well at something then it's easier to stay motivated which makes you work even harder at it.
Personally I spent a lot of time playing FPS games when I was younger but never quite got to the standard for serious tournament play. OTOH I have a friend who got a spot in a well ranked sponsored counterstrike clan after only about 2 months of play.
On the flipside I never put much effort in at school because most it didn't interest me but I still managed to get better grades than many of the kids who worked much harder and had private tutoring etc.
For example I'm sure I could run pretty fast if I trained but I'm never going to beat the 100m record because I'm not usain bolt.