Well, it's not mainly Google's or other Browser's fault.
Apple is also a memory/battery hog, but Apple tries to freeze(a.k.a. App Nap) and over-optimize all in favor of their battery runtime. In a few cases it's good, in others it isn't, it's more often a trade off.
I would prefer to give a bit of iDevice battery runtime to be able to run application services of my choice in the background, but Apple does not allow this. That's why you can't use IRC Apps on iOS without having a bouncer, otherwise you would flood the Channels with join and disconnect messages due to Apple's Application freezes, and probably get banned.
On macOS,Windows,Android you have the freedom to run anything you like, or any service you like in the background, this of course costs battery. Apple also tries to freeze these Apps, but they don't always succeed.
See this as a car's stop-start technology, i hate that kind of things, it often adds more harm than benefits.
That's also one of the reasons why Apple keeps releasing updates and aggressively tries to fix battery drain over and over in vain, because they are constantly over-optimizing on the edge of what's doable in term of battery.
They are constantly fighting with their own features and often have to castrate and over-optimize their own software for the sake of battery runtime promises, small abnormalities shakes their whole system:
Apple is preparing a fix for an issue causing some Apple Watches to experience excessive battery drain after being updated to watchOS 10.1, the...
www.macrumors.com
It's also one of the reasons why you often stumble over forum topics about safari annoyingly auto closing tabs, safari not snappy, iOS annoyingly killing apps and games, etc. in conjunction with low RAM and battery runtime.
In this case I wouldn't blame Chrome, simply because Apple has the tendency to over-optimize their Apps, and because Google might have a different view of what's important and what kind of trade off they accept in term of battery consumption.