You make a great point as Tensor chips are not exactly known for being powerful and yet they do great with AI (even though some of it is done in the cloud).Its nothing to do with the A17 chips, Tensor runs gemini fine.
It's all about the RAM and Apple has skimped on it for YEARS, now they're playing catch up and its come to bite them in the butt for being so cheap.
ALL new pixels have 8GB of RAM, even the $499/£449 Pixel 8a so it can handle some gemini nano stuff.
Only the iPhone 15 Pros have 8GB RAM which is embarrassing and means everyone else will miss out.
I remember wondering why the hell Apple launched the 14 Pro/Pro Max with 6GB RAM as it seemed as though it would become an Achilles heal for them down the line as that was the 3rd generation of Pro iPhones with 6GB RAM.
Now we finally have some parity between iPhone Pro, iPad Pro (+ iPad Air M1 and up) and MacBooks all starting at 8GB RAM.