There has been a lot of similar work on iOS. Check out the WWDC videos at developer.apple.com a year or more likely two back. It is quite amazing what can be do

There has been a lot of similar work on iOS. Check out the WWDC videos at developer.apple.com a year or more likely two back. It is quite amazing what can be done by schedulers and proper use of resources. I guess these optimizations have also found their way back into macOS and Safari on the laptop platform. Considering the release frequency who knows for sure but at least Apple claims their broswer is very efficient. It is worth noting that some of the changes go really deep in the architecture and are not easy to pull off. I think lack of system level focus on low battery and the need to do deep changes in the OS are the reasons for the considerable lateness of Microsoft on this front.