wifi vs. LTE
background app refresh
location services
contrast/brightness
live wallpaper vs. stills
push notifications for email
battery percentage icon
raise to wake
auto downloads
bluetooth
airdrop
fitness tracker
Just to name a few. There's more but I don't have time to write them all out. Long story short, your newer iPhone has way more tech in it than just aligning your apps and letting it sit on the couch for a few hours to see the battery drain. I say again you test is a sham. Not apples to apples.
To be completely fair you can't compare without a controlled environment.
That would be like the auto industry comparing a 2014 Chevy Cruze to a 2017 Chevy Corvette 8-cyl and wondering why it uses more gas than the latter. Even though it's been driven down the same roads, at the same time of day with the same driver, same level of traffic, radio to highway ratio. Impossible to compare when you look at the builds under the hood.