At none of the full-stack jobs I've had would it have been possible to deliver a competitive product just on the web platform. The web platform sucks. You need a general purpose programming language to deliver an sufficiently-complex application.
No form validation before you submit sucks. Page reloads on every action sucks. A native select that don't show you what you're typing sucks. Alerts that can't be styled sucks. The list goes on and on.
The idea that web components slot and template give you close to the same flexibility in functionality that a component library in a programming language does is absurd.