[tantalor]

Why: because otherwise the service, which is supposed to be private, is no longer private.

I dunno how it would work, maybe something like a third-party push? Why does everything have to be channeled through central service? A service like Signal could operate its own push channel.

[satchlj]

Notice how SimpleX (https://simplex.chat/) has no push notifications by default because of this issue.

[daveoc64]

Apple doesn't support any third-party push platforms, and they are restricted on Android to preserve battery life.