That doesn't actually seem very good to me?
I get 3:30 SOT with mine in my crappy signal area being on Lte/3G all day (no wifi till the evening)
I get around 13-14 hours with device on and routinely 3-3.5 SOT and that's with no messing with Google other than google location history turned off.
Auto brightness enabled with slider at 75-100%
Bluetooth turned on - connected to car audio for around 40 - 60 minutes. Taking about 30mins ~ 60mins a day on the phone. Listening to headphones. Taking at least a dozen photos outdoors and then auto backed up to Google Photos & edited in Snapseed... Reading Tapatalk / Google Play Newstand. 2 mac Email accounts on PUSH. Gmail on PUSH. Etc ... Facebook & Facebook Pages Manager with notifications coming in ... I don't really game on my mobiles.
But with all that routine and only basic disabling of apps that I don't use on it such as S-Voice, and with location history off - I get 3 to 3.5 SOT pretty much all the time.
Now if you were getting the 5-6hr SOT others are claiming to get I'd be super impressed - but 3.5 on LTE/cellular is what I would have thought 'normal'... ?
It honestly doesn't seem to be related to Google or Google services at all to me as I can't see the 'benefit' from that result.