Hm, I distinguish between skill and strategy. One can have good skills (not make misplays on playing out a strategy) without picking the optimal strategy. Vice-versa, someone can make the better strategic decision, and just play it out badly.
I should probably specify what I mean by skill and strategy, because people will disagree.
To me, a strategy is choosing the engine, the general battle plan, the stuff you can decide on T1. This can include some mid-game scenarios and decisions that you plan ahead, depending on how familiar you are with the strategy. Typically for high level players, the most likely end-game situations should be clear in your mind.
Skill are decisions (mostly card play order, card options, buying priority and endgame) that occur during the game.
As for the winning strategy always being the one where you learn most, I just disagree.