I was wrong and Apple does replace battery for a very reasonable fee of $79 (https://support.apple.com/iphone/repair/battery-power https://support.apple.com/iph

I was wrong and Apple does replace battery for a very reasonable fee of $79 (https://support.apple.com/iphone/repair/battery-power https://support.apple.com/iphone/repair/battery-power). Hmph. TIL! Can't edit the original post any more so I'll leave this here.