Between really good players and decks it is a key to the design and function of the game. Like I said: same tournament players keep winning and placing high in tournaments despite often playing decks which many other players also play. It's not good enough to identify some of the strongest possible decks in the environment and put one of them together; you have to actually play it.
I'm sure there are play groups or tournaments in which Magic feels different. But it is, at heart, a game of collection, construction, and lucky hands. That there is a variable level of at-the-table skill and that it sometimes makes a difference does not mean that said at-the-table skill is a key to the design and function of the game.