MPC-HC is a superb media player but it is not surprising to see this happen. Interest in maintaining open source Windows applications written in C/Win32/C++/MFC is going to keep dropping as there are not as many people with the skills or motivation to do it. Especially for something as complex as a media player. Even on the Linux side I have seen a drop in the number of full blown media players being developed, they…
Plus, legal streaming video/audio has become ubiquitous in the US, and Chromecast/Fire TV/Roku are far cheaper than building a Home Theater PC (or even converting an old video game console or Linux box into one).
I haven't tried the Roku/Fire etc though, so they may be good too.