Google still lets you use your own push notification service. It will just be correctly reported as using more battery. The evil thing is not providing a GPL-compatible library for connecting to that service, but I'd be surprised if that isn't remedied.
Not quite. Apps have always been held to accounting for the amount of battery and clockcycles they use. The only change here is that a notification is now required for an app to deploy a persistent service. If you request the absolute lowest priority for your notification, your app winds up in the list of apps which are "running" in the background (mainly because the stuff way down at the bottom is too easily missed). If you don't request the lowest priority notification, then your notification text says whatever you'd like it to say and your app doesn't feature in the default notification.
...and there are plenty of good reasons to explicitly register as a foreground service.
I agree with you that someone's bound to crank out a GPL-compatible lib for interfacing with FCM sooner or later.
