Seems to me that the semantics behind the word is changing. Don't know what it is supposed to mean now, though. Of course it is the best iPhone ever made. It's the most recent one. And even though that should be clear from the get go, they have always made that part clear in the all the keynotes before without having to add a 'pro' into what already is a weird statement.
NB: I'm a happy iPhone user since the 3GS and currently have an iPhone X.
1. http://screenshots.200ok.ch/screenshot_2019_09_10-2495e490.p...