They're entering the market so late,
I don't think so, not because MS have been making phone OS for a decade, but because iOS and Android are so young too. After all, Android is just two years old and iPhone has not finished its fourth year yet. Indeed, they've been doing great in these short years, but that doesn't mean they've guaranteed they're eternal success in the mobile industry.
Even though we had a basic distaste for patents, the game is what it is, and patents are essential in modern corporations, if only as a defensive measure.
I really appreciate their work at mocking patents law system, but I can't agree with this part. While we can't change patent laws, we can at least avoid having them. We're not forced to patent our ideas just to protect them, because nobody can make sure the very same patents won't be used for suing other developers. I live in Iran and our patent system isn't as silly and as serious as America's, but I'm trying to avoid even this. I've come with an idea for a new Persian soft keyboard for our own commercial product. Everybody says "it's so innovative. How are you going to patent this?" I'm totally avoiding this, even at the risk of our brand new idea being copied by the others. Fortunately my company is supporting this, but alas, our chance for changing behavior of big companies is even less than odds of changing patent laws.
"I am, therefore I am." -- Akira