OP here. The steel-man argument for React is not that it is faster at rendering. It cannot be, because it ultimately relies on the same DOM that everyone else does to do the job, and it has to set up a massive JS data structure to do what it does, which uses a lot of memory and has big GC costs. Arguments that assert that the React virtual DOM are faster than the native/shadow DOM are simply wrong [1]. Even the React team admits this [2] (though back in the day, they made a number of puffed-up claims about speed that never made sense).

The principle argument in favor of React today are developer ergonomics. People don't have to manually alter individual elements anymore -- they just describe state, and React takes care of the UI change set. On top of that, you have components, etc., that are debatably more pleasant to work with, and at the least create an ecosystem advantage for users of the framework. One can certainly see the argument for something like facebook, where there are probably dozens of different things changing independently at any given time.

But that said, one really has to question whether React makes sense anymore, given LLMs. Back when the alternative was that someone had to bespoke code every UI component, it might have been worth taking the hit of having to adopt the entire React ecosystem. But now that LLMs are writing the code, there's really no argument for developer ergonomics, and suddenly, things like "rewriting URL handling in JS" are pure liabilities.

[1] Though sadly, many front-end devs don't know this.

[2] https://rossenahuh.netlify.app/React/react-concept-1---virtu...