For me, it was how the announcements were made, they did seem to just feel like they had a massive "Wow" factor.
Even way back on the first iPhone announcement - When Steve was on stage and talking about the Palm and Blackberry devices having "physical keyboards", and that he had merged it all with the iPod with touch screens, to me that seemed like a massive jump. (OK I admit, at the time I was very much in the camp of "my Blackberry's keyboard is the finest!", but I watch the announcement back again... there was a very Steve Jobs finesse to the whole thing!).
The more recent announcements have kinda been a bit "meh", and I think maybe it's just that - I think a new type of device that has not been thought about, would bring back the "Wow" factor again.
I think, just for me anyway, that jumping over the releases (so skip a release and upgrade), I see more of a jump, than say if I was going between each version.
Anyway, my thoughts - and I don't know - maybe others see the same with the announcements not quite as they used to be - due to the slowness of "upgrades" to the product.
Maybe you’ve grown up some since then? New phones are fun gadgets, but in the end, it’s just a phone.
Now (or at least for now) the changes have become more iterative. The delta between several generations are still nice, but between individual generations are less enticing to immediately upgrade.
In the end this is not bad. Upgrading a still perfectly working product every 1 or 2 years is quite insane and taxing for the environment. A lot of credit should go to Apple for maintaining iOS support for old iPhones. This makes it possible for people to keep their phones longer or hand them down. Or for people with lower incomes to buy older generations and still get upgrades.
Of course, slower upgrade cycles are bad for manufacturers. So it's smart of Apple to increase revenue through services (Apple Music, Arcade, Apple TV+, iCloud Storage), rather than forcing their customers to upgrade perfectly-fine devices.
Perhaps there's a smoother motion, double clicking, then face-id then press. To me, the finger print sensor just means I'm tapping my phone on the sensor.
You could have said the same about your iPhone 7. What features of the 7 made you WANT to switch compared to earlier models?
"People don’t know what they want until you show it to them." -Steve Jobs