I think it’s honestly more likely that Apple AI has very little RAM headroom with the 6GB in a regular 15, notice that all the devices that support AAI have at least 8GB of RAM.Yup and apple knew this; hence iphone 15s (non pro) and earlier are locked out of the new features (AI), which they gambled on being the main draw but unsurprisingly blew up in their face since people with a 14pro have even less reason to upgrade if they don't care about AI.
Other manufacturers are certainly putting in the effort to differentiate themselves. Are many of the features gimmicks? probably; but apple doesn't do anything at all. And people are hungry for a change that'll differentiate the iphone; even if it's a gimmick, be it folding, active cooling, 3d, under screen camera, active cooling, pop out camera or a secondary e-ink screen. All these are features trialled to varying success by other manufacturers. They are very hit and miss but at least are a point of differentiation.
My bet is that Apple never intended to release it as early as they did but were forced to by how quickly AI because a “must have” spec to tout (whether people actually cared about it or not).
If they’d released it with the 17s, which seems to be about when the final pieces will be released anyway, and it also supported all 4 16s and the 15 pro no one would really be complaining