Yup, hence the rest of my post:Honestly I think competition is still the reason. Some companies are opting for silicon-carbon batteries and pushing things forward, they could make the phones even thinner for a lighter phone, but are often opting to push more mAh.
Example:
iPhone 17 Pro Max 4,823 mAh (physical SIM variant)
iPhone 17 Pro Max 5,088 mAh (eSIM-only variant)
OnePlus 13 (6000mAh silicon-carbon battery)
Xiaomi 17 Pro Max (7500mAh silicon-carbon battery)
Apple's probably just trying to hit an arbitrary marketing number of hours spec, like 45 hours (the 17 Pro Max has "up to 39 hours" by comparison).
Apple’s trying to make the iPhone Pro Max the iPhone Ultra when they should have just made an Ultra to match the Apple Watch Ultra.