>> People don't want everything tied to one identity, one service, one login.
I think this is exactly what _most_ people want.
With password management specifically, Apple has had a Chrome extension available for a while now which has allowed me to use it on other browsers/platforms. Not ideal, but good enough for most.
On top of that, they don't lock you in with passwords. You can easily import and export your passwords, just like you can with 1Password.
Apple Music has had a web client for a long time. iTunes has been on Windows for 20+ years and Apple Music was supported via that until recently when they built an Apple Music specific app.