Microsoft over the last 13 years has flopped around from one idea to another. Their attitude has been build first, worry about identity second. They've rushed around, trying something, failing, rushing into another thing. Even within the space of one push they lack consistency. The Surface ads might be well-made but they're completely all over the place in tone, attitude and feature emphasis. Think about it: there was the liquid metal one, then the dancing clicking one, then this one. The first was hardcore/intense, the second one was exuberant/dizzying, the third was calm/productive. What's the common link? Where's the consistency in their messaging?
Think about Apple's strategy in contrast. Their product strategy, company image, attitude and presentation has basically been one smooth progression from the iPod to the iPhone 5S. The image they've presented has been the epitome of stability and consistency. It's not that they don't make mistakes or make strategy shifts - it's just that Apple astutely realises that it's best to make these changes subtly. It's only techy people like us who notice shifts in emphasis (specs don't matter > A7 64-bit processor). Everyone else loves it. They're not saying the same things over and over again - their messages and emphasis changes over time, but the change is gradual and smooth. Each product, each launch, each ad builds on top of the last.
It's not to say that there aren't recurrent themes in Microsoft's messaging - but the difference between the two is night and day. And what's the result? Apple makes vast amounts of money - all without seeming to lift a finger convincing people to buy their products. They're reaping the fruits of taking the time to work out their strategy early on, and sticking to that strategy.
That's the problem for Microsoft - this is a game where it's your behaviour over years, not months, that matters most. Until they really learn and absorb that lesson they are extremely vulnerable I think.