iPhone 4s battery capacity:1420mah
iphone 4S :1470mah
iphone5:1440mha
iphone5s:1560mha
iphone SE:1642mAh
iphone 6:2915mAh
I own an iphone 5 ,but it only can be used to play games 3-4 hours continuously.
Max has a very valid point, but also it's silly to look at battery capacity and think that is equal to how the battery life would be, you are painting a broad brush that doesn't make sense.
For an Android phone (and even that depends on the phone), I would agree to an extent. Not every phone optimizes the battery in the same way. iOS is really good with how they manage the battery. Some Android phones are also good.
I had a 5s (secondhand) and I still got a day and a little bit with normal usage. Now that I have an SE, I basically get two days of charge with normal usage. If I use something like maps, that can go down to a day and a half. Right now, I charged my phone sometime Wednesday night. It's Friday morning here and I am on day 2 after charging at 44%. I'm thinking that I should be fine at work today but we'll see.
By your logic, this can't happen. I had a 5x, and even though it was solid, the battery life left little to be desired. It survived through the day and sometimes just barely. This is a phone with a 2700 mAh battery.