Dev here : you are 100% right that battery life is not optimized for in most cases.
For one it is hard to measure, and many devs don't really know/care about it.
FCM is a boon in this regard. So are the restrictions that Android is adding to background processing. They are technically not that necessary ... except that you can't trust any app not to abuse it, so the new model is so much better.
Also, thanks Google for finally forcing apps to target the last version or so of this OS so they have to adopt all these new optimizations, whether they want to or not.
For one it is hard to measure, and many devs don't really know/care about it.
FCM is a boon in this regard. So are the restrictions that Android is adding to background processing. They are technically not that necessary ... except that you can't trust any app not to abuse it, so the new model is so much better.
Also, thanks Google for finally forcing apps to target the last version or so of this OS so they have to adopt all these new optimizations, whether they want to or not.