I usually spend my days outside, roaming the city, sitting in parks and cafes. I have a 13mini and started to carry a lightweight power bank in my backpack because it tends to run empty before I get back home, which is a problem with electronic ticket for public transport.

A lot of people will also simply prefer the convenience of not having to plug their phone in more often than necessary. They have it in their backpack or purse, which makes it extra inconvenient to think of taking it out just to charge plus needing a cable and charger in multiple places, compared to the evenings when you may remove multiple items from it.

I have a 16 Pro and every so often something runs in the background that destroys my battery in half a day. I still don’t know what it is. The settings don’t make it clear.

I haven’t complained about the battery life on the Air, but I’d rather have a bigger battery to the point of eliminating the camera bump, than having a marginally thinner phone that shoves everything in a bigger relative bump.

You aren't curious at all. You have formed an opinion. :)

Apple recognizes the deficiency, hence they created the battery accessory which they would love to up-self.

Step 1: Reduce battery life

Step 2: Sell battery accessory, profit.