I use Apple Music, but purely to listen to music I don't want to pay for, and to discover new music. After having to spend hours rebuilding my library after it was ruined by iTunes Match in 2011, I refuse to store my library in the cloud.
If they get rid of iTunes - which, I don't see frankly - I will be forced to switch to a different program. I need a local library with playcounts, etc. Apple Music simply doesn't work for those purposes.
In addition, while a lot of people stream, many rural areas simply cannot handle streaming HD or 4K video, so I'm sure many people prefer to download video and watch locally over their network.