I understand your view, but it's just a lens you are used to looking at. At the bottom of the rabbit-hole, you model data and state like you do on the backend a

I understand your view, but it's just a lens you are used to looking at. At the bottom of the rabbit-hole, you model data and state like you do on the backend and you map that via provided UI layer functions and objects to the renderer. Yes, there are edge case quirks but most of them is stuff you don't need to care about, and when you do, are a google search away. A good frontend-of-the-frontend developer is great at state management and deriving state from the UI model the designer presented it and the data model the backend presented. I believe backend developers have the same skill, just lack experience/"passion" in applying it on the UI end.