Because PMP is only still alive because of a ■■■■ storm in this forum, Plex planned to pull the plug on PMP and currently only supplies bug fixes for it but no new features (as far as I know). The normal windows user is expected to use Plex for Windows, while PMP can be used when problems arise with the former product, like advanced audio passthrough. Probably, noobs get less confused when they are only given one option to choose from.
… or the cause of the ■■■■ storm - TV View vanishing along with the ONLY thing that has it - PMP.
If Plex is holding off on adding PMP’s link to the Apps section in the hopes those naked savages that burned this forum to the ground have forgotten - they have not.