I have a Nexus 6, which is two to three years old, and was, for the 1st time running a couple of benchmarks on my phone to see how it performed against Nexus 6 phones when they were brand new as you can look up review tests from back then.
Guess, what, my 2 - 3 year old phone is giving results just the same as those brand new ones.
A review article said this:
"Nexus 6 battery life is excellent, judging from our tests. Behind its 6-inch AMOLED is a mighty 3220mAh capacity battery, the same as the Samsung Galaxy Note 4
Then.....
iPhone 6 Plus has a 2,915 mAH battery
iPhone 6s Plus has a 2,915 mAh battery
iPhone 7 Plus has a 2,900mAh battery
iPhone 8 Plus has a 2,675mAh battery
Notice a trend here?
And Apple are saying, ahhhh, well, you can't expect batteries to last forever?
Hey Apple, how about not making your battery smaller every year as you know dam well they won't last as long and be able to perform as well for as long.
You think Apple management and Apple engineers are stupid and don't know what they are doing and how long a battery will last and be able to supply top power as they are idiot and don't know or test anything?
No. Apple are VERY clever and know exactly what they are doing.
Which should worry you more, as you can forgive someone stupid as they may not realise things. But this is all deliberate.