Well it’s still hosted under px4/dronecode github/control, integrated into the PX4 buildchain, and it’s dual licensed to Apache which essentially means it’s permissively licensed like the rest of dronecode. Historically MP has been much closer tied to Ardupilot (hosted and integrated into Ardupilot github) and was used to quickly implement features as they came up because of the existing relationship and the great responsive support from MP. The majority of GCS support/effort in Ardupilot for years went towards MP. This is great, nothing wrong with that, but no point trying to rewrite history otherwise.
There’s been a big step forward in the recent past with qgc compatibility/development with Ardupilot which is great. donlakeflyer seems to be super responsive, which is great. qgc is quickly becoming the goto GCS particularly cross platform. I used to use apm_planner2 which had a lot of benefits but quite a few problems as well, now I use QGC. Several of us in the community have asked several times over multiple years for more support for QGC from Ardupilot project so we have a viable cross-platform GCS, rather than focus on a Windows solution. I used to have to run a windows VM just to run MP, recently I find I have to fall back to that less and less, which is a huge win for the ecosystem as a whole as the number of people running Windows decreases by the day and particularly in techie/gadget circles is probably in the minority by now. Choice is always a good thing, but in Ardupilot case I’m not sure it has been very productive as there has not been enough resources to support the different choices - I feel a combined effort would have produced a better single useful product.