Microsoft is in an unlucky spot. They sell to businesses and are trying to transition to something closer to Apple's business model, which is kind of a tricky proposition. Consumer and business have totally different buying cycles and expectations.
Also, Apple spent like a decade rebuilding their business to make it work before the iPhone happened. It started with the iMac, then iPod, then iPhone, then iPad, but with each one they learned something, killed some businesses, started new businesses, and in general worked to keep getting better at what they do.
Microsoft is only a year or two maybe into trying to do the same and until recently they haven't had the same kind of singular focus on it because they are just so freeking big. Apple was big, but Microsoft is a company of 99,139 people.
Think about moving that many different interests in the same direction. That takes time.