At least half the people posting here have no idea what they're talking about wrt WMC. For the record, WMC, or Windows Media Center, is NOT the same thing as Windows Media Player. For all I know they might have once shared some of the same code base and codecs, but they're two different programs that have come with the past few versions of Windows. Both play media files, but only Windows Media Center is a complete Set Top Box replacement (provided you also have a WMC remote and a TV tuner card), with an automatically updated and very complete program guide, recording and playback features, watching and pausing live TV, etc. WMP does none of these, except for playback, and then only manually with non-encrypted content.
Microsoft is dumping Windows Media Center in Windows 10, NOT Windows Media Player. I suppose that some folks here mean the former despite referring to it as the latter, as the naming has always been somewhat confusing, but I'm guessing that most simply don't know the difference and thus don't know what they're talking about, adding to the confusion.
The reason Microsoft is giving is that very few people use WMC, which I'm inclined to believe given that it's a bit of a pain to set up, you need additional equipment from multiple sources, and it helps to be technically proficient and patient. Plus, people are moving to streaming media these days, and WMC isn't well set-up to handle streaming, although it used to have some streaming add-ons that MS disabled. There are 3rd party add-ons, but, again, you need to be proficient and patient, and most people are not, preferring to plug in a stick and get going.
I love WMC and have been using it for years, and it sucks that MS is removing it from future versions of Windows. I'll be keeping my Win7 WMC HTPC up and running for as long as it works, and installing Win10 on a newer PC that I hope to build within the next year. Hopefully I'll be able to watch live TV on it over my network, streaming from my Win7 HTPC, which I currently often do in a small window in the corner of my screen.
Personally, I think that MS is making a mistake by not updating WMC to be able to better handle streaming media and keeping it as a part of Windows, both for backward compatibility with traditional TV tuner-based viewing, recording and viewing, and to compete with the various streaming front ends out there such as Roku, Fire and Apple TV. They're going to have to come out with their own version of the latter eventually, so why not leverage a product they already make to do so? Stupid and inexplicable, like so many moves by Microsoft.