Microsoft still dominates the increasingly irrelevant and dying desktop PC market
Fallacy. The desktop is, and will remain relevant.
Fallacy. The PC market is NOT dying.
The PC market is in the midst of a correction.
Prior to the latest rounds of smartphone/tablet introduction, people were primarily using PCs in situations where a full-blown Wintel system was complete and utter overkill.
With touchscreen smartphones and tablets becoming more or less ubiquitous over the last 3-5 years, we're seeing people looking to replace their older desktop/media/laptop PCs with something, and finding that tablets and the like fit the need better and at a better price point than a full-blown desktop/laptop.
Additionally, in business, we're seeing virtualization starting to make inroads into reversing the trend of moving from centralized resources to localized resources.
As noted, modern Wintel hardware is GROTESQUELY overpowered for most office productivity uses. And in lots of businesses, servers are wasting massive power on idle cycles. On top of that, the support costs, even with dedicated personnel, can be astronomical.
So, instead of dropping a $500-1000 system on everyone's desk, they're virtualizing. Users get a thin client or RDP into a terminal server and work from there.
This way, the business can lock down their platform, deliver only the software needed for the business (saving them money), and allows them to be more agile, since they can set up an office pretty much ANYWHERE, so long as they have internet connectivity.
Now, neither the virtualization market, nor the smartphone/tablet markets have hit critical mass yet. So there's likely to be a bit more of a drain from the desktop PC market for a bit. But it'll eventually peter out and the PC market, while smaller, will still be there. Additionally, it'll allow PC manufacturers to better utilize their resources to deliver products that fit their new market. Rather than shotgunning product all over the place.
So, anyone who's trying to sell you the "The PC is dying" line, basically doesn't know what they're talking about.