I'm on an iPhone 13 since launch (almost 5 years ago) and still see no reason to upgrade. There just hasn't been anything 'exciting' in phones in many years.
EDIT: should add, I've only used 50% of the 256GB storage and battery life is still fine (comfortably gets through an entire day+night). But I'm not a heavy phone user so that's perhaps atypical for a 5yo phone.