To be honest, I usually compare poker to rpg games. In rpg games, although luck is a factor (and many times it is a stat itself, as it is in the D&D games or Bethesda's rpgs) that can affect, for example, critical strikes, you cannot rely on that all along all the game storyline.
Same happens in poker, although you can get lucky (Imagine you have 2-7o and you bluffed AI against A-K, flop comes A A 4, turn spits a 2, and by the river you get another 2) you cannot rely on that luck for every hand you play. Skills like calculating the outs and the odds will make your game stronger, also knowing how to move frome tight to loose gamestyle, and mainly having your tilt-O-meter under control.
All in all, although luck is involved, is not the main factor. No one has ever won a wpt only by being lucky, I believe and hope.