Good Point! The phone is also heavier and thicker than the 7.
Here is what I see happening:
2017: iphone 8 and 10(X)
2018: Iphone 9 no Plus(with Face ID/Touch ID) and Iphone 10S and 10S+ (With FACE ID/Touch ID/Apple in house OLED)
2019: Apple Phone, this will end the iPhone and number series.
Tim Cook spent like 15 minutes explaining how fingerprints are inferior to to facial recognition. 50,000:1 vs. 1,000,000:1 false positives.
Touch ID isn't coming back on a new phone.
Why would Apple launch an iPhone 9 when they've already launched an X?
The iPhone numbering will always continue to remind consumers they have a phone in need of upgrading next year. Removing numbers removes that reminder.