Microsoft made the HEVC-Codec optional since Build 1709 which means if you want to use the codec you have to manual install it. This can be done through the Windows Store. This is a pain in the ass because since it isn’t pre-installed a lot of applications may have trouble, like Netflix or applications which are depending on the codec.
However Netflix still works with Edge (in 4K) but for old MPEG-2 encoded movies or new HEVC related material you have to manually install it. At least both of the codecs are free available. DVD-playback is under Windows 8/10 not free, you have to pay 15€.
Personally I think this has to do something with license reasons but there is no official statement why Microsoft decided make this step. This definitely cries for a mod or repack to integrate the mentioned codec’s in Windows back again, maybe I’ll make a guide about it – let me know if you’re interested.