lets assume two best poker players out there have two best pair cards, AA and KK. At this time, they have slightly equal chance of winning, no matter how skilful they are, AA couldn't fold preflop and KK as well, so what determines the winner is only one thing, luck, there is no skill involved, and mostly we saw this kind of situation, poker is just a game of luck and chance, skill is invalid where others are as good as us, forget about level, just they are good enough.
I have a guy playing, relies only on luck and all. Constantly playing, as the last time, it turns out as usual not veryI think it depends who is playing. Some people play only luck and have no real grasp on how to play. Players rely on mostly practice and dedication to knowing all they can about the game and play accordingly. Like everything else, the more you apply the tactics you know are right, the luckier you get. Just plain luck is for people just starting out, not real players.