According to Ben Drawbaugh at Engadget, the Media Center team was disbanded after Windows 7 shipped in 2009. So the writing has been on the wall for years. Sure, it was a great software product, but it was never packaged into hardware to sell it to the average customer. And cable companies wanted nothing to do with Microsoft in the early 2000's because they feared Microsoft's power (yes, oh look at the irony).
Regardless, we can see some of the Media Center DNA in the Xbox One guide, though of course, no direct recording, just IR blasters. Needless to say, one hopes we are on the cusp of getting TV delivered over the Internet which will make this all a moot point.