Well they can only do so much thanks to patents.
Companies don't exist to innovate, they exist to make money. Capitalism tries to create an environment where innovation = more money but it isn't perfect. Right now Apple's techniques are far-and-away making the most money as far as the general public goes, so in absence of any better ideas MS wants to be like them. I am neither surprised nor disturbed by the trend.
Apple's influence has been both positive and negative. In terms of technology and it's execution/implementation among the general public they've been ground-breaking. They've effectively made computers mainstream, not just as tools that you use for business/communication but something people integrate into their personal lives, that they use as a form of self-expression. This has actually done subtle wonders for the technical community. The concept of a geek is now considered cool, computer nerds now enjoy a great deal of common respect they haven't really had before.
Being a college student, the paradigm shift is especially obvious in the nature of my fellow Engineering majors. More women are choosing that route, and I know a few Electrical Engineers who are full-out frat guys when they're not working. The Geeks aren't just inheriting the earth, they're merging with it. Much of this is thanks in large part to Apple, and it's a very positive aspect IMO.
On the flip side, Apple is pretty tyrannical as corporations go. Steve Jobs established the aggressive stance and his successors seem intent on continuing with that doctrine. Their patent wars are in many ways as pathetic as any ever seen from a rational standpoint, but they drag them out regardless. Likewise they've created a very closed ecosystem, which isn't the best for innovation given its prominence.