Or this is when their phone dies, or they got fed up with their Android phone, or they're handing their existing phone off to a kid and getting a new one, or... thousands of other possibilities. It feels like your list of scenarios doesn't extend much beyond what applies to you, your friends/coworkers, or others that hang out on MacRumors. With millions of new phones selling every week, people are coming to that purchase from all sorts of situations.
This may come as a shock, but not everyone spends their time hanging out on Apple rumor sites. Not everyone can wait over a year, and not everyone cares to - say your phone breaks, would you wait over a year to replace it, and just go without a phone until then?
[doublepost=1564431727][/doublepost]Part of the reason that has faded was Apple taking an interest in curbing the lines outside the stores (I recall a report of someone, perhaps Angela Ahrendts, feeling that wasn't a good look). A lot of the phones are sold online these days. If you look at "there used to be long lines the first day and now there aren't" and come away with "nobody buys iPhones any more", you're misreading the data.