I don’t think they’re stupid but somehow my dad, who could always program my grandpa’s VCR and put together high end AV setups in his youth can’t set up his own entertainment center equipment anymore.
I struggle with phone UIs but that feels like mostly because I can’t be bothered to guess at the “intuitive” ways I can touch a screen that do different things across apps. For instance, some of my video apps are double tap to fill screen, others are outward pinch (is there a word for that?), or a press of certain buttons, or they just don’t do it.