people have different strengths and perspectives (the non-sphericalness of real people) so it's not surprising that folks gravitate towards an area of strength/interest even if they can functionally work on the 'full stack'. as a 'full stack' dabbler[0], i enjoy the view layer stuff the most, but not so much with the js-dominant frontends of current fashion. for that reason, i'm really digging hotwire as a retro-futurist take on server-side-rendered-but-reactive web dev (along with cousins like livewire & htmx).
[0]: product manager who likes to make stuff, in my case