Did Microsoft miss key trends? Maybe a few but who doesn't.
Microsoft saw and got involved in most of those trends they "missed" and even often got there well ahead of the parties that own the markets today.
In 2000 I was hired by Microsoft. One of the big initiatives was to make tablet PCs a reality. Microsoft spent years working on marketing consumer smartphones before the iPhone. That Microsoft lost a leading position in the market for computing devices is surprising given how much effort they put into devices eventually popularized by other companies, particularly Google and Apple.
Why doesn't Microsoft own the tablet and consumer smart phone market right now? The answer must be in execution rather than understanding of where the market was headed. Why couldn't they develop (and why can't they still develop) products folks like in these areas?
When I was there the mentality was that Microsoft would be first to market, would fail for a few major releases but still beat everyone else with a quality product. Yet they spent time producing products nobody wanted while first Apple and later Google ended up walking away with the tablet and consumer smartphone markets.
What went wrong? That's the real question.